Which one of the following statements expresses a true proportion?

A. 7:9 = 8:9
B. 54:9 = 6:3
C. 2:1 = 1:2
D. 3:4 = 9:12

The mean of a set of data is -3.82 and its standard deviation is 2.31. find the z score for a value of 3.99.

On saturday a souvenir shop had 125 customers.sixty four percent of the costumers paid with a credit card. how many costumers paid with cash?

Two cyclists 84 miles apart start riding toward each other at the same. one cycles 2 times as fast as the other. if they meet 4 hours later, what is the speed (in mi/h) of the faster cyclist?