GRE Quant Foundation Assessment Test - Arithmetic

GRE Quant Problem Solving
1

I would appreciate your explanation for this particular question from the GRE Quant Foundation Assessment Test (Arithmetic).

My calculations were as follows: 50/2 = 25; 50/2^2 =12; 50/2^3=6; 50/2^4=3; 50/2^5=1 . So in total 25+12+6+3+1 = 47. Why is the answer 23?

Thanks for your help!

3

You need a pair of 2 for one 4, right? For that reason, you consider doing something like \operatorname{floor} (47/2) = 23 to count the pairs of 2’s you can have, which is equivalent to counting how many 4’s you can have.

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