We have a question: The local school is holding a big fair to raise money for 5 classes that want to go on a trip. 150 people came to the party and paid a total of $368 for entrance tickets. There was a raffle which brought in $343. The sale of cakes and drinks brought $279. At the end of the fair, the principal of the school shared the money raised between the 5 classes. How much money did each class receive?
And an answer: 198
So how you got the answer?
First, let's calculate the total amount of money collected, which is 368 + 343 + 279 = $990. Let us now share this sum between the 5 classes: 990 / 5 = $198.

We have a question: Bill started reading a book on the first day of April. He read 8 pages every day and by the 12th of April, he had covered two-thirds of the book. How many pages does the book have?
And an answer: 144
So how you got the answer?
He read 8 pages every day for 12 days for a total of 8 * 12 = 96 pages. 96 pages is the same as two - thirds of the total number of pages which means: number of pages * (2 / 3) = 96. Therefore the total number of pages is 96 * (3 / 2) = 144 pages.

We have a question: In ten years, I'll be twice my brother's age. The sum of our ages will then be 45 years old. How old am I now?
And an answer: 20
So how you got the answer?
Let X be my age now. In ten years, I'll be X + 10 years old. In ten years, my brother will be (X + 10) * 1 / 2 years old. In ten years, (X + 10) + (X + 10) * 1 / 2 = 45. So (X + 10) * 3 / 2 = 45. X + 10 = 45 * 2 / 3 = 30. X = 30 - 10 = 20 years old.