vinay1983 wrote:If d= 1/(2^3)*(5^7) is expressed as terminating decimal, how many non zero digits will d have?

A. 1
B. 2
C. 3
D. 7
E. 10

OA: B

OG 13, Digits. Also what is the frequency of such concepts or questions being tested on the GMAT?.

d = 1/(2^3*5^7)
= 2^4/(2^7*5^7)
= 2^4/10^7
= 16/10^7
= 0.00...016

Total number of non-zero digits = 2

Choose B

To answer your question, it's difficult to put a number on the frequency of any concept in quant. All I can say is that it will depend on the difficulty levels of the questions you've solved till that point in time. The higher difficulty levels will try to give a question that requires multiple concepts or a concept not frequently used (for example, the number of factors of a number).
The above question looks like a medium-tough difficulty question.

Cheers