1.
If 5^12 x 125 = 5^3x, find the value of x
Correct Answer
D. 5
Explanation
To find the value of x in the equation 5^12 x 125 = 5^3x, you can use the properties of exponents to equate the powers of 5 on both sides:
5^12 x 125 = 5^3x
First, simplify the left side:
5^12 x 125 = 5^12 x 5^3
Now, apply the rule for multiplying numbers with the same base when you have the same base raised to different exponents; you add the exponents:
5^(12 + 3) = 5^15
So, the equation becomes:
5^15 = 5^3x
Now that the bases are the same (both 5), you can equate the exponents:
15 = 3x
To solve for x, divide both sides by 3:
15 / 3 = x
x = 5
So, the value of x is 5.
2.
6.37 x 10-4 in its usual form:
Correct Answer
D. 0.000637
Explanation
The given number, 6.37 x 10-4, is in scientific notation. In scientific notation, a number is expressed as a decimal multiplied by a power of 10. In this case, 6.37 x 10-4 means that the decimal 6.37 is multiplied by 10 raised to the power of -4. To convert it to its usual form, we move the decimal point 4 places to the left, resulting in 0.000637. Therefore, the correct answer is 0.000637.
3.
What is to be multiplied by (-15/16) to get 5/6 ?
Correct Answer
B. -8/9
Explanation
To find the number that needs to be multiplied by (-15/16) to get 5/6, we can set up a proportion. Let the unknown number be represented by x. So, (-15/16) * x = 5/6. To solve for x, we can cross-multiply and then divide both sides by (-15/16). This simplifies to x = (5/6) * (-16/15), which equals -8/9. Therefore, the correct answer is -8/9.
4.
Which property is this 5/6 -+ 2/3 = 2/3 + 5/6
Correct Answer
B. Commutative
Explanation
The given equation 5/6 -+ 2/3 = 2/3 + 5/6 shows that the order of addition or subtraction does not affect the result. The terms 5/6 and 2/3 can be rearranged on either side of the equation, and the result will still be the same. This property is known as the commutative property of addition.
5.
Which is bigger; -9/13 or -11/26
Correct Answer
-9/13
Explanation
To compare the two fractions, we need to find a common denominator. The least common denominator for 13 and 26 is 26. Converting -9/13 to have a denominator of 26, we get -18/26.
Since -18/26 is less than -11/26, -9/13 is bigger than -11/26.
6.
50 times of 8 is equal to
Correct Answer
D. 400
Explanation
The correct answer is 400 because when you multiply 50 by 8, you get 400.
7.
The missing terms in multiple of 3: 3, 6, 9, __, 15 is
Correct Answer
12
Explanation
The missing terms in the sequence are multiples of 3. The given sequence starts with 3, then adds 3 each time to get the next term. Therefore, the missing term after 9 would be 12, as it is the next multiple of 3 in the sequence.
8.
What is to be added to 5/4 to get 1?
Correct Answer
-1/4
Explanation
To find what needs to be added to 5/4 to get 1, we subtract 5/4 from 1. This can be done by finding a common denominator, which is 4 in this case. So, 1 can be written as 4/4. Subtracting 5/4 from 4/4 gives us -1/4. Therefore, -1/4 needs to be added to 5/4 to get 1.
9.
Smallest prime number that is an even number too
Correct Answer
C. 2
Explanation
The smallest prime number is 2, and it is also an even number because it is divisible by 2.
10.
The multiplicative identity of rational number is
Correct Answer
B. 1
Explanation
The multiplicative identity of a rational number is the number that, when multiplied by any rational number, gives the same rational number as the result. In this case, the number 1 satisfies this condition. When any rational number is multiplied by 1, the result is always the same rational number. Therefore, the correct answer is 1.