GRE Quiz | GRE Quantitative 2 | Question 15

Which of the following is equivalent to (10^z + 10^{z + 1}) / (10^{z – 1} + 10^z)?

(A) 2 / 3
(B) 3 / 2
(C) 10
(D) 1
(E) 1 / 10

Answer: (C)
Explanation:

= (10z + 10z + 1) / (10z - 1 + 10z)
= 10z(1 +  10) / 10z((1 / 10) + 1) 
= 11 / (11/10)
= 10 

So, option (C) is correct.
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