Question

A boy bought two Guppies and his sister bought six Tetras at the beginning of the month. One month later, the number of guppies in the boy's tank had doubled. And the number of tetras in his sister's tank increased by five. If both fish populations continue to grow in the same manner, after how many months will the boy have more fish?

Answer 1

After three months, the sister will have more fish than the boy.

Step-by-step explanation:

To determine after how many months the boy will have more fish, we need to compare the growth rate of the guppies and the tetras. After one month, the boy's guppies doubled in number, so he now has 4 guppies. The sister's tetras increased by 5, so she now has 11 tetras.

The difference in the number of fish is 11 - 4 = 7 in favor of the sister. If we continue the same growth rate, the guppies will double every month while the tetras will increase by 5 every month. After two months, the boy will have 8 guppies and the sister will have 16 tetras (11 + 5 + 5).

The difference is now 16 - 8 = 8 in favor of the sister. After three months, the boy will have 16 guppies and the sister will have 21 tetras (16 + 5). The difference is now 21 - 16 = 5 in favor of the sister. Therefore, it will take at least three months for the sister to have more fish than the boy.