The car-rental agency charges $30/day for a car, or $190 for the first week for a rental that lasts an entire week or longer. Jennie rented a car for 11 days. How much, in dollars, did she pay for the rental? Give the rationale and then the answer.
Let's think step by step. The first 7 days were $190. There were 11 - 7 = 4 days left. The additional 4 days were 4 * 30 = 120. And 190 + 120 = 310.. The answer is: 310.

Tommy is looking at his change collection. He has 10 more dimes than pennies. He has twice as many nickels as dimes. He has 4 quarters. He has 10 times as many pennies as quarters. How many nickels does he have? Give the rationale and then the answer.
Let's think step by step. Tommy has 40 pennies because 10 x 4 = 40. Tommy has 50 dimes because 40 + 10 = 50. Tommy has 100 nickels because 50 x 2 = 100.. The answer is: 100.

David found $12 on the street. He then gave it to his friend Evan who has $1 and needed to buy a watch worth $20. How much does Evan still need? Give the rationale and then the answer.
Let's think step by step. The total amount Evan has is $1 + $12 = $13. So Evan still needs $20 - $13 = $7.. The answer is: 7.