Question

If 7x=9y, y/z = 7/5 , then x/z = (A) 2/7 (B) 7/9 (C) 9/5 (D) 9/7 (E) 5/9

Answer 1

(C) 9/5

Explanation:

There are several ways to go at this. Here's one of them.

Multiply the second equation by 9/9, then substitute for 9y from the first equation.

(9y)/(9z) = 7/5

(7x)/(9z) = 7/5

Now, multiply by 9/7.

x/z = (9/7)(7/5) = (9·7)/(5·7)

x/z = 9/5