[Question]Jennifer is building tanks to hold her goldfish. She built 3 tanks that will hold 15 fish each, heated, and filled them. She plans to build the rest of the tanks equipped with heaters, and they will hold 10 fish each. If she needs to build enough tanks to house a total of 75 fish, how many more will she need to build?
[Answer]With the tanks already built it has room for 3 tanks * 15 fish / tank = 45 fish. The total of fish that still lack space is 75 fish - 45 fish = 30 fish. This means Jennifer needs 30 fish / 10 fish / tank = 3 tanks of 10 fish. The answer is 3.

[Question]Madeline has 5 boxes with 24 crayons in each. She noticed that 5/8 of the crayons in the 2 boxes were not yet used. In the 2 other boxes, only 2/3 of the crayons were used while the last box was not entirely used. How many unused crayons did Madeline have?
[Answer]Two boxes of crayons have 24 x 5 / 8 = 15 unused crayons from each box. So, a total of 15 x 2 = 30 unused crayons are in the two boxes. For the other 2 boxes, there are 24 x 2 / 3 = 16 used crayons from each box. Hence, there are 24 - 16 = 8 unused crayons. So, a total of 8 x 2 = 16 unused crayons are in the other two boxes. Therefore, Madeline has a total of 30 + 16 + 24 = 70 unused crayons. The answer is 70.

[Question]To make 3 liters of ketchup Ashley needs 69 kg of tomatoes. How many kilos of tomatoes does Ashley need to make 5 liters of ketchup?
[Answer]One liter of ketchup is made from 69 kg / 3 liters = 23 kg / liter of tomatoes. Ashley needs 23 kg / liter * 5 liters = 115 kg of tomatoes. The answer is 115.

[Question]Yanna bought ten shirts at $5 each and three pairs of sandals at $3 each. How much change did she get back if she gave a one hundred dollar bill?
[Answer]
Ten shirts cost 10 x $5 = $50. And, three pairs of sandals cost 3 x $3 = $9. Thus, she spent $50 + $9 = $59. Therefore, she got back change of $100 - $59 = $41. The answer is 41.