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

Redeem

please show me the right method

This topic has expert replies
Post new topic Post Reply
Previous Topic Next Topic
Legendary Member
Posts: 1159
Joined: Wed Apr 16, 2008 10:35 pm
Thanked: 56 times

please show me the right method

by raunekk » Fri May 30, 2008 4:12 am
hey guys ..do u have a specific method for solving this kinda questions...??


q)
The function f is defined for each positive three-digit integer n by f(n) = 2x3y5z, where x, y and z
are the hundreds, tens, and units digits of n, respectively. If m and v are three-digit positive
integers such that f(m) = 9f(v), then m-v = ?
A. 8
B. 9
C. 18
D. 20
E. 80
Top
Source: — Problem Solving |
Senior | Next Rank: 100 Posts
Posts: 43
Joined: Sun Feb 18, 2007 5:59 am

by keepsmilinyaar » Fri May 30, 2008 6:50 am
no offense but are you sure you got the question correct??
Top
Master | Next Rank: 500 Posts
Posts: 178
Joined: Wed May 14, 2008 3:51 pm
Thanked: 16 times
Followed by:1 members
GMAT Score:99%+

by egybs » Fri May 30, 2008 9:03 am
agreed.. the question, as asked, is impossible.
Top
Master | Next Rank: 500 Posts
Posts: 192
Joined: Tue Apr 29, 2008 7:41 am
Thanked: 14 times

by aatech » Fri May 30, 2008 9:15 am
six digits no multiplied by 9 resulting into another 6 digit no.... weird
Top
Legendary Member
Posts: 1159
Joined: Wed Apr 16, 2008 10:35 pm
Thanked: 56 times

its like tis

by raunekk » Fri May 30, 2008 10:01 am
Its nt 6 digits......its 2^x3^y5^z...
Top
Senior | Next Rank: 100 Posts
Posts: 37
Joined: Sat May 24, 2008 8:59 pm

by silvia928 » Fri May 30, 2008 10:08 am
i think the question states correctly cuz I run into an exactly same question and having problem with....
can anyone help...the answer should be 20.
Top
Master | Next Rank: 500 Posts
Posts: 178
Joined: Wed May 14, 2008 3:51 pm
Thanked: 16 times
Followed by:1 members
GMAT Score:99%+

by egybs » Fri May 30, 2008 10:14 am
How can 2xxxxx *9 = 2xxxxx??

Something was mixed up in the question... it's probably something subtle.. but i'm fairly certain it's there.
Top
Master | Next Rank: 500 Posts
Posts: 178
Joined: Wed May 14, 2008 3:51 pm
Thanked: 16 times
Followed by:1 members
GMAT Score:99%+

Re: its like tis

by egybs » Fri May 30, 2008 10:21 am
raunekk wrote:Its nt 6 digits......its 2^x3^y5^z...
Ahh there you go... In that case it's fairly easy.

let's assume that V = 111

So we get 2^1*3^1*5^1 = 2*3*5 = 30

f(V) = 30
Therefore F(M) = 270

If we factor 270, we find 3*3*3*5*2 which is equal to 2^1*3^3*5^1

Therefore M = 131

131-111 = 20

Or alternatively you could just give it some thought. Since we know f(m) has to be 9 times bigger than f(v), and 9 = 3^2.. we know that there will always be two more 3s in the factor of f(m) than f(v). Which leads you to the answer of 20.
Top
Legendary Member
Posts: 1159
Joined: Wed Apr 16, 2008 10:35 pm
Thanked: 56 times

thanks

by raunekk » Fri May 30, 2008 9:29 pm
thanks egybs...i made an assumption tat x,y, and z cant be equal.. but as such i tried wit x=1,y=2 n z=3.. and got d answer... thanks:)




btw can u give me some advice as to how to improve my score in quant.. i m a bit weak at it..i dont seem 2 develop tat logic.!!can u suggest me some good books.. i am weak at permutation combination,number system and word problems...pls advice
Top
Post new topic Post Reply
• Page 1 of 1