Class 9 Math Masters: Conquer The Quiz Challenge!
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Are you ready to embark on an exciting journey through the Class 9 Math Quiz? Mathematics can seem like a complex puzzle, but it's a captivating world of patterns and logic waiting to be explored. By understanding its applications and recognizing the elegance of solving equations, you can unlock its true potential. This quiz is designed to gauge your knowledge of ninth-grade math concepts and challenge your problem-solving skills. Are you prepared to take on the challenge and demonstrate your mathematical prowess? Let's dive in and see how well you fare in this fascinating world of numbers and equations
Class 9 Math Quiz Questions and Answers
- 1.
If 30% of a number is 18, what is 150% of that number?
- A.
54
- B.
60
- C.
90
- D.
150
Correct Answer
C. 90Explanation
First, find the whole number: If 30% of the number is 18, then 10% is 6 (18 / 3 = 6). Therefore, 100% of the number is 60 (6 x 10 = 60).
To find 150%, calculate 50% of the number, which is 30 (60 / 2 = 30). Add this to the original number: 60 + 30 = 90.Rate this question:
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- 2.
If x + 5 = 10, then what is the value of x?
- A.
5
- B.
10
- C.
15
- D.
-5
Correct Answer
A. 5Explanation
To solve for x in the equation x + 5 = 10, you need to isolate x. You do this by subtracting 5 from both sides of the equation.Here’s the step-by-step solution:x + 5 - 5 = 10 - 5,which simplifies to:x = 5.Thus, x equals 5. This solution can be verified by substituting 5 back into the original equation: 5 + 5 = 10, which is true. Therefore, the correct value of x is 5.Rate this question:
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- 3.
Given the equation x2+4x+3=0, what are the values of x?
- A.
2 or 3
- B.
-1 or -3
- C.
1 or 3
- D.
5 or -1
Correct Answer
B. -1 or -3Explanation
To solve the quadratic equation x^2 + 4x + 3 = 0, you can factorize it:
(x + 3)(x + 1) = 0
Setting each factor equal to zero gives:
x + 3 = 0
Solving for x, x = -3
x + 1 = 0
Solving for x, x = -1
Thus, the solutions for x are -1 and -3. These are the values that make the original equation true when substituted back into it.Rate this question:
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- 4.
What is the next number in the sequence: 3, 7, 15, 31, ?
- A.
47
- B.
63
- C.
72
- D.
58
Correct Answer
B. 63Explanation
The given sequence is increasing, and each number is obtained by doubling the previous number and then adding 1.
Starting with 3:
3 * 2 + 1 = 7
7 * 2 + 1 = 15
15 * 2 + 1 = 31
To find the next number, we apply the same pattern:
31 * 2 + 1 = 63
So, the next number in the sequence is 63.Rate this question:
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- 5.
Given the equation y2+ 4=20, what are the values of y?
- A.
4 only
- B.
-4 only
- C.
4 or -4
- D.
16
Correct Answer
C. 4 or -4Explanation
To solve the equation y^2 + 4 = 20, first subtract 4 from both sides:
y^2 + 4 - 4 = 20 - 4
This simplifies to:
y^2 = 16
Next, find y by taking the square root of both sides. Remember, squaring a number results in a positive value, and the square root of a positive number has both a positive and negative solution:
y = sqrt(16)
This gives:
y = 4 and y = -4
Therefore, y equals both 4 and -4.Rate this question:
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- 6.
The price of an item increases by 20% and then decreases by 20%. What is the net effect on the price?
- A.
Increased by 4%
- B.
Decreased by 4%
- C.
Increased by 0%
- D.
Increased by 40%
Correct Answer
B. Decreased by 4%Explanation
When the price of an item increases by 20% and then decreases by 20%, the net effect is a decrease in the overall price. Here’s how it works:
Initial Price: Assume the original price is $100.
After 20% Increase:
New price = $100 + 20% of $100 = $100 + $20 = $120.
After 20% Decrease:
New price = $120 - 20% of $120 = $120 - $24 = $96.
So, the net effect is a 4% decrease in the original price. The final price is $96, which is less than the original price.Rate this question:
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- 7.
The ratio of girls to boys in a school is 5:7. If there are 525 girls, how many boys are there?
- A.
375
- B.
625
- C.
735
- D.
325
Correct Answer
C. 735Explanation
The ratio of girls to boys in the school is 5:7. This means for every 5 girls, there are 7 boys. Given there are 525 girls, we first determine how many times the part of the ratio (5) fits into the actual number of girls (525).
Calculate the multiplier for the ratio:
525 (number of girls) / 5 (girl ratio part) = 105
Now, use this multiplier to find the number of boys:
Multiply the boy ratio part by the multiplier:
7 (boy ratio part) x 105 (multiplier) = 735
Therefore, there are 735 boys in the school.Rate this question:
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- 8.
David and John share $455 in the ratio of 2:3, respectively. How much money does John get?
- A.
$182
- B.
$273
- C.
$91
- D.
$175
Correct Answer
B. $273Explanation
David and John share $455 in the ratio of 2:3. This means for every 2 units that David receives, John receives 3 units. To find out how much money each person gets, you first need to determine the total number of parts into which the money is divided:
Total parts = 2 (David) + 3 (John) = 5 parts
Now, calculate the value of one part:
Value of one part = Total money / Total parts = $455 / 5 = $91
Finally, calculate how much John receives by multiplying the value of one part by the number of parts John receives:
Money John receives = 3 parts x $91/part = $273
Therefore, John receives $273.Rate this question:
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- 9.
If x-12y = 0, what is y/x?
- A.
1/6
- B.
12
- C.
1/12
- D.
None
Correct Answer
C. 1/12Explanation
To find the ratio of y/x from the equation x-12y = 0, first rearrange the equation to solve for y in terms of x. By moving all terms involving y to one side and all other terms to the opposite side, we get x = 12y. Now, divide both sides of this equation by x to isolate y/x on one side. This gives us y/x = 1/12. Hence, the value of y/x equals 1/12. This is calculated by dividing the coefficient of y by the coefficient of x in the rearranged equation.Rate this question:
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- 10.
What is 3/20 as a decimal?
- A.
0.3
- B.
0.5
- C.
0.15
- D.
1.5
Correct Answer
C. 0.15Explanation
To convert the fraction 3/20 into a decimal, divide the numerator by the denominator. The calculation is performed by dividing 3 by 20. When you divide 3 by 20, you get 0.15. Therefore, the decimal equivalent of the fraction 3/20 is 0.15. This decimal value directly results from the division process, representing the proportion of 3 parts out of a total of 20 parts.Rate this question:
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- 11.
What is 68/0.00001 expressed as an ordinary number?
- A.
68,000,000
- B.
680000
- C.
68000
- D.
0.00068
Correct Answer
A. 68,000,000Explanation
Dividing by a decimal is the same as multiplying by its reciprocal. The reciprocal of 0.00001 is 100,000. Therefore, 68 divided by 0.00001 is the same as 68 multiplied by 100,000, which equals 6,800,000.Rate this question:
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- 12.
What is the value of 4*4-2*(-3)+6= ?
- A.
17
- B.
28
- C.
-36
- D.
None
Correct Answer
B. 28Explanation
We follow the order of operations (PEMDAS: Parentheses, Exponents, Multiplication and Division (from left to right), Addition and Subtraction (from left to right)):
First, multiply:
4 × 4 = 16
2 × (-3) = -6
Now, substitute these values into the expression:
16 - (-6) + 6
Subtracting a negative is the same as adding:
16 + 6 + 6 = 28Rate this question:
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- 13.
What is the result when you reduce $80 by 11%?
- A.
$8.80
- B.
$71.20
- C.
$69
- D.
None
Correct Answer
B. $71.20Explanation
To find the amount remaining after reducing $80 by 11%, first calculate 11% of $80. Multiply 80 by 0.11 to get the reduction amount. This calculation gives 80 * 0.11 = $8.80. Now, subtract this amount from the original $80 to find the reduced total. The calculation is 80 - 8.80 = $71.20. Therefore, when you reduce $80 by 11%, you will get $71.20. This result is achieved by applying the percentage reduction to the original amount and subtracting the calculated value from the original total.Rate this question:
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- 14.
What is 0.67543 rounded to 2 significant figures?
- A.
0.68
- B.
0.7
- C.
0.67
- D.
0.70
Correct Answer
A. 0.68Explanation
To round the number 0.67543 to 2 significant figures:Identify the first two significant figures, which are 6 and 7.Look at the third digit, which is 5. Since 5 is greater than or equal to 5, you round up the second significant figure (7) to 8.Therefore, 0.67543 rounded to 2 significant figures is 0.68. This process ensures the number is represented accurately while maintaining the specified precision.Rate this question:
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- 15.
What is the simplified form of 5ab - 7ba + 4ab=?
- A.
2ab
- B.
-2ab
- C.
16ab
- D.
None
Correct Answer
A. 2abExplanation
First, recognize that ab and ba are equivalent (since multiplication is commutative). Therefore, we can combine the terms:
5ab−7ab+4ab
Now, combine like terms:
(5−7+4)ab
2ab
Thus, the simplified form of 5ab−7ba+4ab is 2ab.Rate this question:
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- 16.
What is the value of x in the equation 4(x+2)=24?
- A.
X=11/2
- B.
X=4
- C.
X=-4
- D.
X=16
Correct Answer
B. X=4Explanation
To solve the equation 4(x+2)=24
Distribute the 4:
4x+8=24
Subtract 8 from both sides to isolate the term with x:
4x=16
Divide both sides by 4 to solve for x:
x=16/4
Therefore, the value of x is 4.Rate this question:
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- 17.
The sum of three consecutive even numbers is 222. What are the numbers?
- A.
73,74,75
- B.
74,74,74
- C.
72,74,76
- D.
None
Correct Answer
C. 72,74,76Explanation
Let the three consecutive even numbers be
𝑥, x+2, and x+4.
Their sum is given by:
x+(x+2)+(x+4)=222
Combine like terms:
3x+6=222
Subtract 6 from both sides:
3x=216
Divide both sides by 3:
x=72
Therefore, the three consecutive even numbers are:
x=72
x+2=74
x+4=76
So, the numbers are 72, 74, and 76.Rate this question:
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- 18.
The gradient of the line joining (-4,-1) and (4,2) is:
- A.
-3/8
- B.
3/8
- C.
0
- D.
8/3
Correct Answer
B. 3/8Explanation
The gradient of a line is determined by the change in y divided by the change in x between two points on the line. In this case, the change in y is 2 - (-1) = 3 and the change in x is 4 - (-4) = 8. Therefore, the gradient is 3/8.Rate this question:
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- 19.
The gradient of the line y = 4 -2x is:
- A.
4
- B.
2
- C.
-2
- D.
None
Correct Answer
C. -2Explanation
The gradient of a line represents its steepness or slope. In the given equation, y = 4 - 2x, the coefficient of x (-2) represents the slope of the line. Since the coefficient is negative, the line has a negative slope. Therefore, the gradient of the line y = 4 - 2x is -2.Rate this question:
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- 20.
What is the gradient of the line x+3y=9?
- A.
3
- B.
1/3
- C.
-1/3
- D.
None
Correct Answer
C. -1/3Explanation
To find the gradient (or slope) of the line, we need to rearrange the equation into slope-intercept form, which is y = mx + c, where m is the gradient.
Rearrange the equation: x + 3y = 9 3y = -x + 9 y = (-1/3)x + 3
Identify the gradient: Now the equation is in slope-intercept form, and we can see that the gradient (m) is -1/3.Rate this question:
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- 21.
If 2x-3y +4x-7y=0, then what is the value of y/x?
- A.
3/5
- B.
5/3
- C.
5/11
- D.
-3/5
Correct Answer
A. 3/5 -
- 22.
If 2x+5y=18 and x=2, what is the value of 4x+5y?
- A.
20
- B.
19
- C.
22
- D.
21
Correct Answer
C. 22Explanation
First, substitute x=2 into the equation 2x+5y=18:
2(2)+5y=18
4+5y=18
Next, solve for 𝑦 by isolating y:
5y=18−4
5y=14
y=2.8
Now, substitute x=2 and y=2.8 into the expression 4x+5y:
4(2)+5(2.8)
8+14
22
Therefore, the value of 4x+5y is 22.Rate this question:
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- 23.
Factor the quadratic expression: x2+x-30:
- A.
(x+5)(x-6)
- B.
(x-5)(x+6)
- C.
(x-6)(x-5)
- D.
None
Correct Answer
B. (x-5)(x+6)Explanation
The given quadratic expression, x^2 + x - 30, can be factorized as (x - 5)(x + 6). This can be determined by finding two numbers that multiply to give -30 and add up to 1, which are -5 and 6 in this case. Therefore, the correct answer is (x - 5)(x + 6).Rate this question:
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- 24.
Change 36 km/h to meters per second:
- A.
20
- B.
10
- C.
36
- D.
None
Correct Answer
B. 10Explanation
Convert kilometers to meters: 1 kilometer (km) = 1000 meters (m). So, 36 km = 36 * 1000 = 36000 meters.
Convert hours to seconds: 1 hour = 60 minutes, and 1 minute = 60 seconds. So, 1 hour = 60 * 60 = 3600 seconds.
Divide the distance in meters by the time in seconds: 36000 meters / 3600 seconds = 10 meters/second.Rate this question:
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Oct 30, 2024Quiz Edited by
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Expert Reviewed by
Janaisa Harris -
Dec 04, 2010Quiz Created by
Imthiyas Slasa
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