Question: If Katherine has 4 apples and 3 times as many pears in her fridge, how many bananas does she have if she has a total of 21 pieces of fruit?
Answer: Katherine has a total of 3 * 4 apples = 12 pears. She therefore had 4 apples + 12 pears = 16 apples and pears. We know she has 21 total pieces of fruit, so this means she must have 21 total - 16 = 5 bananas. The answer is 5.

Question: A long wire is cut into three smaller pieces in the ratio of 7:3:2. If the shortest piece is 16 cm, how long was the entire wire before it was cut?
Answer: Since the shortest part is consists of 2 parts, then each part is equal to 16 cm / 2 = 8 cm. The whole wire was cut into 7 + 3 + 2 = 12 parts. Hence, the wire was 8 cm x 12 = 96 cm long. The answer is 96.

Question: Polly and Gerald went for a fun afternoon riding mini race cars at the munchkin track, which is a one-quarter mile circular track. Polly managed to circle the track 12 times in one half hour, but Gerald's car was malfunctioning, and he only moved at an average speed half of what Polly did. What speed did Gerald's car average, in miles per hour?
Answer: Polly circled the one - quarter mile track 12 times in 0.5 hours at a speed of 12 / 0.5 = 24 circuits of the track per hour. 24 / 4 = 6 miles per hour. Gerald traveled at a speed half of what Polly traveled for an average speed of 6 / 2 = 3 miles per hour. The answer is 3.

Question: John gets lost on his way home. His normal trip is 150 miles and would take him 3 hours. He ends up driving 50 miles out of the way and has to get back on track. How long did the trip take if he kept the same speed?
Answer:
His speed is 150 / 3 = 50 mph. He was detoured 50 * 2 = 100 miles. So that adds 100 / 50 = 2 hours. So the total trip was 3 + 2 = 5 hours. The answer is 5.