GMAT Prep QA question
If n and y are positive integers and 450y=n^3, which of the following must be an integer?
1. y/(3×2^2×5)
2.y/(3^2x2x5)
3.y/(3x2x5^2)
a. None
b. i only
c. ii only
d. iii only
e. i, ii and iii
OA is B Cant we take higher values of and n and y and satisify the condition ,in that case answer will be E.
Eg- y=5^4×3^4×2^5, So N = (5x3x2)^2
Hi Jacob,
You reasoning would be right if this question is “could be” question.
But this is a “Must-be” question, whenever GMAT Asks “must be”, replace it with “always” to understand better.
So, here second and third statement not always true.
If we take y = 3*5*2^2 then only statement I is true.
Infact we just need minimum “y” value as 3 * 5 * 2^2.
Hope this clear your doubt.