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

Redeem

integer n

This topic has expert replies
Post new topic Post Reply
Previous Topic Next Topic
User avatar
Legendary Member
Posts: 1022
Joined: Mon Jul 20, 2009 11:49 pm
Location: Gandhinagar
Thanked: 41 times
Followed by:2 members

integer n

by shashank.ism » Tue Feb 09, 2010 7:18 am
Suppose n is an integer such that the sum of the digits of n is 2, and 10^10 < n < 10^11. The number of different values for n is

11
10
9
8
7
My Websites:
www.mba.webmaggu.com - India's social Network for MBA Aspirants

www.deal.webmaggu.com -India's online discount, coupon, free stuff informer.

www.dictionary.webmaggu.com - A compact free online dictionary with images.

Nothing is Impossible, even Impossible says I'm possible.
Top
Source: — Problem Solving |
User avatar
Legendary Member
Posts: 1275
Joined: Thu Sep 21, 2006 11:13 pm
Location: Arabian Sea
Thanked: 125 times
Followed by:2 members

by ajith » Tue Feb 09, 2010 11:10 am
shashank.ism wrote:Suppose n is an integer such that the sum of the digits of n is 2, and 10^10 < n < 10^11. The number of different values for n is

11
10
9
8
7
there is only 1 starting with 2 and rest 10 zeros
Starting with 1 there are 10 of them (11--9 zeros 101 --8zeros....)

In total 11 of them
Always borrow money from a pessimist, he doesn't expect to be paid back.
Top
User avatar
Legendary Member
Posts: 1022
Joined: Mon Jul 20, 2009 11:49 pm
Location: Gandhinagar
Thanked: 41 times
Followed by:2 members

by shashank.ism » Tue Feb 09, 2010 11:31 am
ajith wrote:
shashank.ism wrote:Suppose n is an integer such that the sum of the digits of n is 2, and 10^10 < n < 10^11. The number of different values for n is

11
10
9
8
7
there is only 1 starting with 2 and rest 10 zeros
Starting with 1 there are 10 of them (11--9 zeros 101 --8zeros....)

In total 11 of them
Hmm nice apporach to the problem...
If the sum of no. is like 7 or 8 then what we will do is there any methodical peocedure....
My Websites:
www.mba.webmaggu.com - India's social Network for MBA Aspirants

www.deal.webmaggu.com -India's online discount, coupon, free stuff informer.

www.dictionary.webmaggu.com - A compact free online dictionary with images.

Nothing is Impossible, even Impossible says I'm possible.
Top
User avatar
Legendary Member
Posts: 1132
Joined: Mon Jul 20, 2009 3:38 am
Location: India
Thanked: 64 times
Followed by:6 members
GMAT Score:760

by harsh.champ » Tue Feb 09, 2010 12:08 pm
shashank.ism wrote:
ajith wrote:
shashank.ism wrote:Suppose n is an integer such that the sum of the digits of n is 2, and 10^10 < n < 10^11. The number of different values for n is

11
10
9
8
7
there is only 1 starting with 2 and rest 10 zeros
Starting with 1 there are 10 of them (11--9 zeros 101 --8zeros....)

In total 11 of them
Hmm nice apporach to the problem...
If the sum of no. is like 7 or 8 then what we will do is there any methodical peocedure....
10^10 < n < 10 x 10^10
Now,if the sum is 2
Case 1 -:2 1's are there
10^10 means 10 zeros
so we have 11 places.
Selection of 1 place can be done in 10 ways.
Case 2:- 2 x 10^10

Hence ,11 A
It takes time and effort to explain, so if my comment helped you please press Thanks button :)



Just because something is hard doesn't mean you shouldn't try,it means you should just try harder.

"Keep Walking" - Johnny Walker :P
Top
Post new topic Post Reply
• Page 1 of 1