Mrs. Chiu checks 30 problems in 2 minutes. How many problems can Mrs. Chiu check in 68 minutes?

2men and 7 boys can do a piece of working 4 days.it is done by 4 men and 4 boys in 3 days how long would it take for 1man or one boy to do it alone

(98 points) i need with 5 questions. answer definitions are welcomed, but not necessary.

5500 dollars is placed in an account with an annual interest rate of 6.5%. to the nearest tenth of a year, how long will it take for the account value to reach 19700 dollars?