chondro48
If n is a positive integer, is n a multiple of 121?
(1) 44 is the greatest common divisor of 220 and n
(2) 968 is the least common multiple of 121 and n
+1 kudo, if this is deemed worthy of 700-level.
Okay, a pretty challenging question (+1 kudos). took about 3 minutes. What is the source?
Basically the question is asking whether \(\frac{n}{121}\)=integer or \(\frac{n}{11*11}\)=integer?
statement (1): 44 is the greatest common divisor of 220 and n
220=
2x
2x5x
11n=
2x
2x
11 (minimum numbers that n must have since GCD = 44=2*2*11).
other than the above given values(must) of n, other additional values could be 2^anything x any number x 11^anything.
if n=2*2*11=44, then is \(\frac{44}{121}\)=integer? NO
if n=2*2*2*5*11= 440 NO
but if n=2*2*11*11=484, then is \(\frac{484}{121}\)=integer?YES!
Different answers. INSUFFICIENT!
statement (2):968 is the least common multiple of 121 and n
LCM=968=2x2x2x11x11
121=11*11
n= 2x2x2 or 2x2x2x11 or 2x2x2x11x11
if n= 2x2x2=8, then is \(\frac{8}{121}\)=integer? NO
if n=2x2x2x11=88, then is \(\frac{88}{121}\)=integer? NO
if n=2x2x2x11x11, then is \(\frac{(2*2*2*11*11)}{(11*11)}\)? YES!
Different answers. INSUFFICIENT!
Statement 1+2
If you notice, same values were tested in each statements. Indirectly, both the statements were similar. Different answers. INSUFFICIENT!
thus, answer is option E