Joe and kim washed 27 cars in 6 hours. the next day, they had more and washed twice as many cars in the same amount of time. what was their average car-washing rate on the second day?
a. 4.5 cars per hour
b. 5 cars per hour
c. 6.2 cars per hour
d. 9 cars per hour

Write two subtraction equations that are equivalent to 5 + 12 = 17.

Two customers went to a post office. first customer paid $12 for 14 and 5 envelopes the second paid 24.80 for 10 postcards and 15 envelopes. what is cost of each envelope?

The first-serve percentage of a tennis player in a match is normally distributed with a standard deviation of 4.3%. if a sample of 15 random matches of the player is taken, the mean first-serve percentage is found to be 26.4%. what is the margin of error of the sample mean? a. 0.086% b. 0.533% c. 1.11% d. 2.22%