BREAKING: Target Test Prep releases Brand New 2026 On Demand GMAT prep course

Redeem

interesting DS

This topic has expert replies
Post new topic Post Reply
Previous Topic Next Topic
Master | Next Rank: 500 Posts
Posts: 371
Joined: Tue Apr 29, 2008 10:16 am
Thanked: 6 times
Followed by:1 members

interesting DS

by vaivish » Tue Aug 05, 2008 8:00 am
If m+2=10^n, where m and n are positive integers, n=?
(1) The sum of digits of m is 116.
(2) n>10


OA is A.
Top
Source: — Data Sufficiency |
User avatar
Legendary Member
Posts: 986
Joined: Wed Dec 20, 2006 11:07 am
Location: India
Thanked: 51 times
Followed by:1 members

Re: interesting DS

by gabriel » Fri Aug 08, 2008 10:38 am
vaivish wrote:If m+2=10^n, where m and n are positive integers, n=?
(1) The sum of digits of m is 116.
(2) n>10


OA is A.
Since n is a positive integer we can say that m is of the form 999.. (x times)8. Eg. if n=4 then m=9998

Now, according to the first statement the sum of the digits of m is 116, that is 9*x+8=116, so 9x=108 and that means x= 12. So m is of the form 9999 .. (12 times)8 .. add 2 to this and count the number of zeroes and that will be the value of n ..

statement 2 is not worth discussing, it gives us nothing to work with. So the answer is A.
Top
Post new topic Post Reply
• Page 1 of 1