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

Question

Mathematics

Carina Madden

1 January, 07:43

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

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Answers (1)

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Ali Dickerson · Answer 1

(C) 9/5

Step-by-step 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