Fred has 3 times as many dimes as quarters. How many dimes does he have if the value of all the coins is $3.85?

Answer 1

It's easier to find the number of quarters:

10*3q + 25q = 385
55q = 385
q = 7
so, d=3q=21

Answer 2

at 7:00 A.M the temperature was 22 °F. by 2:00 P.M. it had risen to 41 °F. by 7:00 P.M., it was 31 °F. which operation do you need to use to find the change in the number of degrees from 7:00 A.M. to 7:00 P.M