We have a question: Nikka has a 100 stamp collection. Thirty-five percent of her stamps are Chinese, 20% are US stamps, and the rest are Japanese stamps. How many Japanese stamps does Nikka have?
And an answer: 45
So how you got the answer?
Nikka has 100 x 35 / 100 = 35 Chinese stamps. She has 100 x 20 / 100 = 20 US stamps. So, Nikka has 35 + 20 = 55 stamps that are not Japanese. Thus, Nikka has 100 - 55 = 45 Japanese stamps.

We have a question: Ben spends 20% of his after-tax income on his car. If his car payment is $400 and he pays 1/3 of his gross income in taxes, how much does he make per month before taxes?
And an answer: 3000
So how you got the answer?
First divide that amount of the car payment by 20% to find Ben's after - tax salary: $400 / .2 = $2000. Then find the proportion of his salary Ben keeps after taxes by subtracting the tax rate from 1: 1 - 1 / 3 = 2 / 3. Then divide Ben's after - tax salary by the proportion of his salary he keeps to find his before - tax salary: $2000 / 2 / 3 = $3000.

We have a question: Matt is playing basketball. In the first quarter, he made 2-point shots four times and 3-point shots twice. How many points did he score for that quarter?
And an answer: 14
So how you got the answer?
His total score for the 2 - point shots is 2 x 4 = 8. His total score for the 3 - point shots is 3 x 2 = 6. His total score for the first quarter is 8 + 6 = 14.