50 = 2*5^2
n^2 is divisible by 50 implies that it is divisible by 2^2*5^2 (100)
Therefore n is divisible by 10. D.
Ergh. Thats a horrible explanation.
if n is a integer and n²
This topic has expert replies
Source: Beat The GMAT — Problem Solving |
-
scoobydooby
- Legendary Member
- Posts: 1035
- Joined: Wed Aug 27, 2008 10:56 pm
- Thanked: 104 times
- Followed by:1 members
given n²/50=an inetger
=> n²/2*5²=an integer
n² must have 2² and 5² (squares have even powers and given that n is an integer)
=> n must have 2 and 5 ie n must be atleast 10
if n is atleast 10, the greatest divisor can be 10. (the number itself is its greatest divisor)
hence, D
=> n²/2*5²=an integer
n² must have 2² and 5² (squares have even powers and given that n is an integer)
=> n must have 2 and 5 ie n must be atleast 10
if n is atleast 10, the greatest divisor can be 10. (the number itself is its greatest divisor)
hence, D
-
mjjking
- Master | Next Rank: 500 Posts
- Posts: 353
- Joined: Sat Jan 20, 2007 1:29 am
- Location: Italy
- Thanked: 7 times
- GMAT Score:720
It's like the following:
if n^3 is divisible by 240, then what can be the minimum highest factor of n?
You see that 240 = 2^4x3x5
Hence, n must contain at least all these numbers in equal manner:
n n n
2 2 2
3 - -
2 - -
5 - -
From this we can imply that n includes at least a 3, a 5 and 2 2s, hence 60 is a factor of n.
if n^3 is divisible by 240, then what can be the minimum highest factor of n?
You see that 240 = 2^4x3x5
Hence, n must contain at least all these numbers in equal manner:
n n n
2 2 2
3 - -
2 - -
5 - -
From this we can imply that n includes at least a 3, a 5 and 2 2s, hence 60 is a factor of n.
Beat The GMAT - 1st priority
Enter a top MBA program - 2nd priority
Loving my wife: MOST IMPORTANT OF ALL!
REAL THING 1 (AUG 2007): 680 (Q43, V40)
REAL THING 2 (APR 2009): 720 (Q47, V41)
Enter a top MBA program - 2nd priority
Loving my wife: MOST IMPORTANT OF ALL!
REAL THING 1 (AUG 2007): 680 (Q43, V40)
REAL THING 2 (APR 2009): 720 (Q47, V41)
