A farmer living in the countryside has a certain number of children. One day, they followed him to the farm, each one with a bag to collect harvested apples. At the end of the day, each bag was filled with 15 apples each. On their way back home, 2 of the children have eaten 4 apples each and another child sold 7 of his apples. If they had a total of 60 apples left by the time they got home, how many children does the farmer have? Give the rationale and then the answer.
Let's think step by step. 2 children sold 4 apples each which gives 2 * 4 = 8 apples. Another child gave out an additional 7 apples making 8 + 7 = 15 apples removed from the total. There were 60 apples left after these, so the original total must have been 15 + 60 = 75 apples. Each child collected 15 apples so there are 75 / 15 = 5 children.. The answer is: 5.

In a batch of 30 apples, 1/6 are too small and 1/3 are not ripe. The others are perfect. Calculate the number of perfect apples. Give the rationale and then the answer.
Let's think step by step. We first calculate the proportion of all the other apples: 1 / 6 + 1 / 4 + 1 / 12 = 2 / 12 + 3 / 12 + 1 / 12 = 6 / 12. So, the proportion of perfect apples is 12 / 12 - 6 / 12 = 6 / 12 = 0.5. Thus the number of perfect apples is 0.5 * 30 = 15.. The answer is: 15.

Sonja makes her own peanut butter with peanuts and oil in a blender. She uses a ratio of two ounces of oil to smooth out every eight ounces of peanuts. Her last batch of peanut butter weighed 20 ounces. How many ounces of oil did she use? Give the rationale and then the answer.
Let's think step by step. Sonja uses 2 ounces of oil for 8 ounces of peanuts to make 2 + 8 = 10 ounces of peanut butter. Her last batch weighed 20 ounces, so she made 20 / 10 = 2 times her ratio. Thus, she used 2 * 2 = 4 ounces of oil.. The answer is: 4.