We have a question: Angelina is 4 years older than Justin is now. In 5 years, Angelina will be 40 years old. Calculate the age of Justin currently.
And an answer: 31
So how you got the answer?
In five years, Angelina will be 40 years old, meaning currently she is 40 - 5 = 35 years old. Since Angelina is 35 years old right now, and she is four years older than Justin, it means Justin is 35 - 4 = 31 years old.

We have a question: There were 90 people at the summer picnic. There were 50 soda cans, 50 plastic bottles of sparkling water, and 50 glass bottles of juice. One-half of the guests drank soda, one-third of the guests drank sparkling water, and four-fifths of the juices were consumed. How many recyclable cans and bottles were collected?
And an answer: 115
So how you got the answer?
The soda cans were consumed by 90 / 2 = 45 guests. The sparkling water was consumed by 90 / 3 = 30 guests. The juice bottles were consumed by 4 / 5 x 50 = 40 guests. In total there are 45 + 30 + 40 = 115 recyclable cans and bottles.

We have a question: Janet has a business selling custom collars for dogs and cats. If it takes 18 inches of nylon to make a dog collar and 10 inches to make a cat collar, how much nylon does she need to make 9 dog collars and 3 cat collars?
And an answer: 192
So how you got the answer?
First find the total number of inches of nylon used for the dog collars: 18 inches / dog collar * 9 dog collars = 162 inches. Then find the total number of inches of nylon used for the cat collars: 10 inches / cat collar * 3 cat collars = 30 inches. Then add the nylon needed for the cat and dog collars to find the total amount needed: 162 inches + 30 inches = 192 inches.