secretaries

Forum Index GMAT Math Problem Solving

New MBA Student Life Forum: Ask your questions to current MBA students from Harvard, Stanford, Wharton, Kellogg and Haas

Post new topic   Reply to topic

crackgmat007
GMAT Destroyer!



Joined: 20 Feb 2009
Posts: 871

Thanks given: 63
Thanked 10 times in 10 posts
Topic: secretaries
PostSat Nov 07, 2009 4:07 pm Reply with quote
Three secretaries working together can type 36 pages of text in half an hour. If the typing speeds of the secretaries are in a 4:3:2 ratio, how long will it take the slowest-typing secretary working alone to type 52 pages of text?

1 hour and 34 minutes
1 hour and 45 minutes
2 hours and 24 minutes
3 hours and 15 minutes
3 hours and 25 minutes

OA D
Back to top
View user's profile Send private message
Testluv
GMAT Instructor



Joined: 19 Oct 2009
Posts: 299

Thanks given: 1
Thanked 57 times in 54 posts
Location: Toronto

GMAT Score: 800
PostSat Nov 07, 2009 4:52 pm Reply with quote
crackgmat007 wrote:
Three secretaries working together can type 36 pages of text in half an hour. If the typing speeds of the secretaries are in a 4:3:2 ratio, how long will it take the slowest-typing secretary working alone to type 52 pages of text?

1 hour and 34 minutes
1 hour and 45 minutes
2 hours and 24 minutes
3 hours and 15 minutes
3 hours and 25 minutes

OA D
Hi crackgmat007,

Their speeds are in a 4:3:2 ratio. So, if we split the job into 9 (4+3+2) parts, the fastest secretary will have contribued 4/9 towards the job, the middle one 3/9, and the slowest secretary contributed 2/9 towards the job.

So, the slowest secretary manages 2/9 of 36 pages in a half an hour: 2/9 * 36 = 8 pages in a half an hour. Then, her rate per hour is 16 pages per hour.

It will take her 52/16 = 3.25 hours, or three hours and fifteen minutes to type 52 pages. Choose D.
_________________
Kaplan Teacher in Toronto
Back to top
View user's profile Send private message
Thanked by: Ludacrispat26
vivek.kapoor83
GMAT Destroyer!



Joined: 04 Aug 2008
Posts: 833

Thanks given: 13
Thanked 9 times in 8 posts
PostMon Nov 09, 2009 4:10 am Reply with quote
let total x no. of pages
in 1 hr they will type
4x+3x+2x = 72 pages
x = 8
1st type = 4*8 = 32 pages/hr
2nd type = 24 pages/hr
3rd type = 2*8 = 16 pages/hr
So, for typing 52 pages
3 will take
3hr = 48 pages
and for 4 pages = 1/4hr = 15min
hence 3 hrs 15 min
Ans is D/
Back to top
View user's profile Send private message
Display posts from previous:   

Post new topic   Reply to topic All times are GMT - 8 Hours
Page 1 of 1