500 ds test11 #24

This topic has expert replies
Master | Next Rank: 500 Posts
Posts: 269
Joined: Sun Apr 01, 2007 5:41 am

500 ds test11 #24

by dunkin77 » Thu Apr 19, 2007 12:16 pm
24. If b is the product of three consecutive positive integers c, c + 1, and c + 2, is b a multiple of 24 ?

(1) b is a multiple of 3,
(2) c is odd.


Hi,

I thought the answer is E) but actually the answer is A) --- Can anyone please explain??

User avatar
Community Manager
Posts: 789
Joined: Sun Jan 28, 2007 3:51 pm
Location: Silicon valley, California
Thanked: 30 times
Followed by:1 members

Re: 500 ds test11 #24

by jayhawk2001 » Thu Apr 19, 2007 10:07 pm
dunkin77 wrote:24. If b is the product of three consecutive positive integers c, c + 1, and c + 2, is b a multiple of 24 ?

(1) b is a multiple of 3,
(2) c is odd.


Hi,

I thought the answer is E) but actually the answer is A) --- Can anyone please explain??
I'm not sure how it can be A.

Take 3*4*5 - clearly not a multiple of 24.
Take 23*24*25 - clearly a multiple of 24

So, insufficient.

Actually 1 doesn't tell us anything that we already don't know.

Product of 3 consecutive positive integers HAS to be a multiple of 3
3*4*5, 4*5*6, 5*6*7 etc. are all multiples of 3.

Master | Next Rank: 500 Posts
Posts: 269
Joined: Sun Apr 01, 2007 5:41 am

by dunkin77 » Fri Apr 20, 2007 6:28 am
Thank you jay for confirming it. :)

I checked the answer again but it says A) -- I think the answer in textbook must be wrong! :?