Matemática Prof. Aidina 1

1) Uma lesma deve subir um poste de 10 metros de altura. De dia sobe 2m e à noite desce 1m. Em quantos dias atingirá o topo do poste?

11

9

5

The snail climbs 1 meter per day (2 meters up and 1 meter down). To reach the top of the 10-meter pole, it will take 9 days.

Explanation

The snail climbs 1 meter per day (2 meters up and 1 meter down). To reach the top of the 10-meter pole, it will take 9 days.

2) Complete a série seguinte: 80, 40, ...., 19, 17

20

38

22

The series follows a pattern where each number is subtracted by 2. Starting with 80, subtracting 2 gives 78, and continuing this pattern we get 76, 74, and so on. The pattern continues until we reach the number 19, where subtracting 2 would give 17. Therefore, the missing number in the series is 38, as subtracting 2 from 40 gives 38.

Explanation

The series follows a pattern where each number is subtracted by 2. Starting with 80, subtracting 2 gives 78, and continuing this pattern we get 76, 74, and so on. The pattern continues until we reach the number 19, where subtracting 2 would give 17. Therefore, the missing number in the series is 38, as subtracting 2 from 40 gives 38.

3) Três gatos comem três ratos em três minutos. Cem gatos comem cem ratos em quantos minutos?

4

3

100

If three cats can eat three rats in three minutes, it means that each cat takes three minutes to eat one rat. Therefore, if there are 100 cats, each taking three minutes to eat one rat, they will still take three minutes to eat 100 rats. Thus, the correct answer is 3.

Explanation

If three cats can eat three rats in three minutes, it means that each cat takes three minutes to eat one rat. Therefore, if there are 100 cats, each taking three minutes to eat one rat, they will still take three minutes to eat 100 rats. Thus, the correct answer is 3.

4) Que altura tem uma criança que é 2 metros menor que uma árvore de altura igual ao triplo da altura da criança?

1,50m

1,25m

1,00m

The height of the child is 1 meter. This is determined by setting up an equation based on the given information. Let's assume the height of the child is x. The height of the tree is then 3x, as it is equal to three times the height of the child. It is also stated that the child is 2 meters shorter than the tree. So, the equation becomes: x = 3x - 2. Solving this equation, we find that x = 1 meter, which is the height of the child.

Explanation

The height of the child is 1 meter. This is determined by setting up an equation based on the given information. Let's assume the height of the child is x. The height of the tree is then 3x, as it is equal to three times the height of the child. It is also stated that the child is 2 meters shorter than the tree. So, the equation becomes: x = 3x - 2. Solving this equation, we find that x = 1 meter, which is the height of the child.

5) Temos 4 correntes de 3 elos cada uma. Queremos unir as 4 para formar uma corrente fechada. Abrir um elo custa R$ 20,00 e fechar custa R$ 30,00. Quanto devemos gastar?

100

150

200

To form a closed chain, we need to open three links to connect the four chains, which will cost 3 * R$20 = R$60. Then, we need to close the chain, which will cost R$30. Therefore, the total cost will be R$60 + R$30 = R$90. However, the given answer is 150, which is incorrect.

Explanation

To form a closed chain, we need to open three links to connect the four chains, which will cost 3 * R$20 = R$60. Then, we need to close the chain, which will cost R$30. Therefore, the total cost will be R$60 + R$30 = R$90. However, the given answer is 150, which is incorrect.

6) se 1=5 2=12 3=123 4=1234 5=1?

Verdadeiro

Falso ( 5 = 12345)

Nenhuma das alternativas

The given pattern suggests that each number is formed by concatenating the previous numbers in a sequence. For example, 3 is formed by concatenating 1 and 2 (i.e., 1+2=12), and 4 is formed by concatenating 1, 2, and 3 (i.e., 1+2+3=123). Therefore, it can be inferred that 5 is formed by concatenating 1, 2, 3, and 4 (i.e., 1+2+3+4=1234). Hence, the answer "Verdadeiro" (True) is correct.

Explanation

The given pattern suggests that each number is formed by concatenating the previous numbers in a sequence. For example, 3 is formed by concatenating 1 and 2 (i.e., 1+2=12), and 4 is formed by concatenating 1, 2, and 3 (i.e., 1+2+3=123). Therefore, it can be inferred that 5 is formed by concatenating 1, 2, 3, and 4 (i.e., 1+2+3+4=1234). Hence, the answer "Verdadeiro" (True) is correct.

7) Um frasco contém um casal de um tipo de insetos. Esses insetos reproduzem-se e o seu número dobra todos os dias. Em 50 dias o frasco está cheio. Em que dia o frasco esteve pela metade?

24

49

25

Since the number of insects doubles every day, we can work backwards to find the day when the jar was half full. On the 49th day, the number of insects would have doubled 49 times, which means the jar would have been full. Therefore, on the 48th day, the jar would have been half full.

Explanation

Since the number of insects doubles every day, we can work backwards to find the day when the jar was half full. On the 49th day, the number of insects would have doubled 49 times, which means the jar would have been full. Therefore, on the 48th day, the jar would have been half full.