Answer this question:Xander read 20% of his 500-page book in one hour. The next night he read another 20% of the book. On the third night, he read 30% of his book. How many pages does he have left to read?
The first night he read 20% of his 500 - page book so he read .20 * 500 = 100 pages. The book is 500 pages and he read 100 so that leaves 500 - 100 = 400 pages. The second night he reads 20% of the 500 pages so he read .20 * 500 = 100 pages. The book is now 400 pages and he read 100 so that leaves 400 - 100 = 300 pages. The third night he read 30% of the book so he read .30 * 500 = 150 pages. The book is now 300 pages and he read 150 pages so he has 300 - 150 = 150 pages left to read.
The answer is 150.

Answer this question:Corna wants to buy a shirt. The store buys the shirt for $20, but charges 30% for profit. However, the shirt is on sale for 50% off the selling price. What is the price now?
First find how much the store makes in profit: $20 * 0.30 = $6 for profit. Then find the regular selling price: $20 + $6 = $26 total price. Then multiply the regular price by the discount to get $26 * 0.50 = $13 for the final price.
The answer is 13.

Answer this question:A farmer is checking his fields to make sure all of his crops are growing as they should. Rows of corn stalks should produce 9 corn cobs each, and rows of potatoes should produce 30 potatoes each. As he's checking crop quality, he notices that there are more pests than usual and they have destroyed some of his crops. He thinks that half of his crops have been destroyed by the pests. If the farmer has 10 rows of corn stalks and 5 rows of potatoes, how many crops does the farmer still have?
The farmer had a total of 10 rows of corn stalks * 9 corn cobs each = 90 corn cobs. He also had a total of 5 rows of potatoes * 30 potatoes each = 150 potatoes. This was a total of 90 corn cobs + 150 potatoes = 240 crops. Because pests destroyed half of his crops, he now has 240 crops * 0.5 = 120 crops.
The answer is 120.

Answer this question:Kyle goes to basketball practice every day for 2 hours. At practice he spends half of the time shooting and the rest of the time running and weight lifting. If he runs for twice the time he spends weightlifting, how much time in minutes does he spend lifting weight?
Half of the 2 - hour practice is for running and weightlifting, so the time for running and weight lifting is 1 / 2 * 2 hours = 1 hour. If the time he lifts weights is x, then the time he runs is 2x. So the time for running and weight lifting is x + 2x = 3x = 1 hour. Thus 3x = 60 minutes. Thus x = 60 / 3 = 20 minutes spent weight lifting.
The answer is 20.