Lograthims

Karthik12 · Posted: Wed Jul 23, 2008 8:57 pm Post subject: Lograthims

GIven that log 3=0.477, log 7=0.845, log 2=0.301. Find the number of digits in Y if Y=252^10(the power of 10).
1. 12
2. 25
3. 24
4. 30
5. cannot be determined

sudhir3127 · Posted: Wed Jul 23, 2008 9:44 pm Post subject:

IMO 24.

Karthik12 · Posted: Wed Jul 23, 2008 10:40 pm Post subject:

Pls anyone give the answer with sufficient explaination

sudhir3127 · Posted: Wed Jul 23, 2008 10:51 pm Post subject:

Y = 252^10

applying log on both the sides

Log Y= 10 log 252

10 log( 2*2*3*3*7)
log m*n = Log m+ log n

hence its 10 (0.603+0.954+.0854)
= 24.02

whats the OA?

pepeprepa · Posted: Thu Jul 24, 2008 12:19 am Post subject:

Y = 252^10

I trust calculations of sudhir:
Log Y = 24.02

We know that: log 10=1
So we also know
log 10^2=2
log 10^24=24 which is more or less 24.02
log Y=24=log 10^24
Y=10^24
In 10^24 we have 24+1 digits so 25
Y has 25 digits

Tell me if my demonstration has weaknesses, I do not master log.

sudhir3127 · Posted: Thu Jul 24, 2008 12:28 am Post subject:

ya pepeprepa ur right...

it would be 10^24 .i thought it would have 24 digits...

it will have n+1 digits... hence 25..

can someone confirm the OA.

gmatutor · Posted: Thu Jul 24, 2008 1:09 am Post subject: Focused Study

Studying logs may be useful for your MBA course but is not tested on the GMAT, nor in all the official material I have, dating back to 1976, has it ever been tested on the GMAT.

On the mba.com website it mentions that the most important thing a student can do when studying is to focus on those areas that will help them the most. I believe that advice is sound. This is unlikely to help you increase your GMAT score.

pepeprepa · Posted: Thu Jul 24, 2008 1:13 am Post subject:

Ok I did not know logarithms were no on the program of the gmat.

Karthik12 where did you find this question?

Karthik12 · Posted: Thu Jul 24, 2008 2:49 am Post subject:

thank u Guyz

gmattakers · Posted: Thu Oct 30, 2008 3:22 pm Post subject:

I choose C, too