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

Redeem
TTP OnDemand GMAT Video Course
Featured Course

Target Test Prep GMAT OnDemand

Scott Woodbury-Stewart’s private virtual classroom — 400 hours of master-class video lessons for the GMAT Focus Edition.

  • 715+ score guarantee — highest in the industry (99th percentile)
  • 52 chapters · 1,500+ lessons · 4,000+ practice questions
  • 400 hours of video · 1,500+ instructor-led HD smartboard lessons
  • 300,000+ students accepted to Harvard, Stanford, Wharton, Booth & Sloan & more
  • 24/7 live support + weekly Zoom office hours with GMAT instructors
  • TTP AI Assist — 24/7 AI-powered virtual tutor for instant help
  • 1,200+ flashcards + AI-powered study assistant & daily calendar
  • OnDemand, LiveTeach & GMAT Bootcamp formats available
  • Also: GRE, SAT Math & Executive Assessment courses
  • MBA Admissions Consulting now available
  • 🏆 2025 EdTech Breakthrough Award: Test Prep Solution Provider of the Year
  • 200,000+ students served
  • 5-day free trial — $0 to start, no auto-billing, cancel anytime
★★★★★ 5.0 (559 reviews)
130-pt guarantee
$0 to start then $127/mo
Start Free 5-Day Trial Read 559 Reviews →

Need help

Expert replies
Post new topic Post Reply
Previous Topic Next Topic
Junior | Next Rank: 30 Posts
Posts: 12
Joined: Wed Feb 24, 2010 7:09 am
by sohaib_iba » Tue Jun 01, 2010 9:05 am
Jack can do a certain job in 20 days while Tom can do the same job in 25 days. If both do the job together and are paid a total amount of Rs 450. Find the amount that should be given to Jack (assuming that each person is paid according to the ratio of the job done).

A) 200
B) 250
C) 360
D) 380
E) 400

My answer is 200. Please correct me if i m wrong. Thanks
Top
Join the discussion
Log in to postLogin with Googleuse password
QUOTE IN REPLY
Source: — Problem Solving |
Senior | Next Rank: 100 Posts
Posts: 52
Joined: Thu Feb 25, 2010 9:08 am
Thanked: 5 times

by akdayal » Tue Jun 01, 2010 9:17 am
Jack can do a certain job in 20 days while Tom can do the same job in 25 days. If both do the job together and are paid a total amount of Rs 450. Find the amount that should be given to Jack (assuming that each person is paid according to the ratio of the job done).

A) 200
B) 250
C) 360
D) 380
E) 400

My answer is 200. Please correct me if i m wrong. Thanks
ANS: 250.
Money will be distributed in ratio of work done by both.
Wj / Wt = (1/20)/(1/25) = 5/4
Hence Jack will get (5/9)* 450 = 250
Top
Join the discussion
Log in to postLogin with Googleuse password
QUOTE IN REPLY
User avatar
Legendary Member
Posts: 1309
Joined: Wed Mar 17, 2010 11:41 pmFollowed by: 5 members
Thanked: 33 times

by pradeepkaushal9518 » Tue Jun 01, 2010 9:26 am
200 cant be the answer as jack works only in 20 days and tom in 25 days hence jack should be paid more.
Top
Join the discussion
Log in to postLogin with Googleuse password
QUOTE IN REPLY
User avatar
Legendary Member
Posts: 1460
Joined: Tue Dec 29, 2009 1:28 amFollowed by: 7 members
Thanked: 135 times

by selango » Tue Jun 01, 2010 9:30 am
Jack can 1/20 work in 1 day and tom can do 1/25 work in 1 day.

Combined both can complete the work in 100/9 days.

Jack share in 1 day=1/20*450

for 100/9 days= 1/20*450*100/9

=250
Top
Join the discussion
Log in to postLogin with Googleuse password
QUOTE IN REPLY
User avatar
Master | Next Rank: 500 Posts
Posts: 362
Joined: Fri Oct 02, 2009 4:18 amFollowed by: 1 member
Thanked: 26 times

by indiantiger » Tue Jun 01, 2010 9:40 am
Here is my solution

Work done by Jack in one day = 1/20 (as he takes 20 days to finish the job)
Work done by Tom in one day = 1/25

Total work that can be done by both when they work together =
1/20 + 1/25 = 45/(20*25) = 9/100

The amount of work completed by Jack in one day (when both work together is) = (1/20)/(9/100) = 5/9
The amount of work completed by Tom in one day (when both work together is) = (1/25)/(9/100) = 4/9

ratio for jack's portion of work is 5/9

so his share is = 5/9 *450 = 5*50 = 250 (Answer)
"Single Malt is better than Blended"
Top
Join the discussion
Log in to postLogin with Googleuse password
QUOTE IN REPLY
Senior | Next Rank: 100 Posts
Posts: 85
Joined: Sat Aug 15, 2009 4:36 am
Thanked: 19 times

by gmatjedi » Tue Jun 01, 2010 6:27 pm
jack 20 days
tom 25 days

let work done be x
jack does 5x work and tom does 4x work

9x=450
x=50
jack =250
Top
Join the discussion
Log in to postLogin with Googleuse password
QUOTE IN REPLY
GMAT Instructor
Posts: 1302
Joined: Mon Oct 19, 2009 2:13 pmFollowed by: 164 members
Location: Toronto
Thanked: 539 times
GMAT Score:800

by Testluv » Tue Jun 01, 2010 6:28 pm
We don't want to do a bunch of math unless we have to. If we can reason it out with a minimum of math, all the quicker, and therefore all the better. Thus, I'll endorse gmatjedi and akdayal's approach.

Let's reason it out.

Pretend for a moment that Jack can do the job in 1 day while Tom in 2. Then, isn't it clear that Jack works 2/1 times as fast as Tom?

Because Jack in fact does the job in 20 days while it takes Tom 25, Jack works 25/20 or 5/4 times as fast as Tom

Thus, towards the whole job, Jack contributes 5 units for every 4 units contributed by Tom.

In other words, they contribute in a 5:4 ratio, which is a part to part ratio, Jack's part: Tom's part. Thus, the part to final ratio (Jack: Jack + Tom) is just 5/9. And, so, Jack deserves 5/9 of the 450 rupees.
Kaplan Teacher in Toronto
Top
Join the discussion
Log in to postLogin with Googleuse password
QUOTE IN REPLY
Master | Next Rank: 500 Posts
Posts: 112
Joined: Wed Jan 20, 2010 5:46 am
Thanked: 1 times

by Thouraya » Wed Jun 02, 2010 5:13 am
Testluv, I understood ur approach but im doing the mistake in ratios here...I am assuming that because J can do the job in 20 days while T in 25, then J:T is 20:25 which is equal to 4:5, so Jack is contributing 4 out of the 9 not the other way around...I know it doesnt make sense logically cuz he's faster, but from a math point of view, where am I doing the mistake exactly?
Top
Join the discussion
Log in to postLogin with Googleuse password
QUOTE IN REPLY
Legendary Member
Posts: 576
Joined: Sat Mar 13, 2010 8:31 pmFollowed by: 1 member
Thanked: 97 times

by liferocks » Wed Jun 02, 2010 5:28 am
Thouraya wrote:Testluv, I understood ur approach but im doing the mistake in ratios here...I am assuming that because J can do the job in 20 days while T in 25, then J:T is 20:25 which is equal to 4:5, so Jack is contributing 4 out of the 9 not the other way around...I know it doesnt make sense logically cuz he's faster, but from a math point of view, where am I doing the mistake exactly?
J:T=25:20 or 5:4
ratio of money will be amount of job done
"If you don't know where you are going, any road will get you there."
Lewis Carroll
Top
Join the discussion
Log in to postLogin with Googleuse password
QUOTE IN REPLY
GMAT Instructor
Posts: 1302
Joined: Mon Oct 19, 2009 2:13 pmFollowed by: 164 members
Location: Toronto
Thanked: 539 times
GMAT Score:800

by Testluv » Wed Jun 02, 2010 6:53 am
Thouraya wrote:Testluv, I understood ur approach but im doing the mistake in ratios here...I am assuming that because J can do the job in 20 days while T in 25, then J:T is 20:25 which is equal to 4:5, so Jack is contributing 4 out of the 9 not the other way around...I know it doesnt make sense logically cuz he's faster, but from a math point of view, where am I doing the mistake exactly?
Well, let's say Jack's time is 1 day, and Tom's is 2 days. Then it is clear that Jack works twice as fast as Tom, and so J:T contribute in 2:1 ratio.

Let's say that Jack's time is 1 day, and Tom's is 3 days. Then it is clear that Jack works thrice as fast as Tom, and so J:T contribute in 3:1 ratio.

Let's say that Jack's time is 20 days, and Tom's is 25 days. Then, Jack works 25/20 times as fast as Tom, and so J:T contribute in 25:20 ratio or 5:4 ratio.

Work contributed is proportional to rate of work. But rate of work is inversely proportional to time of work (if you do the job in half as much time as me, then you work twice as fast me).
Kaplan Teacher in Toronto
Top
Join the discussion
Log in to postLogin with Googleuse password
QUOTE IN REPLY
Master | Next Rank: 500 Posts
Posts: 112
Joined: Wed Jan 20, 2010 5:46 am
Thanked: 1 times

by Thouraya » Thu Sep 08, 2011 4:08 am
Hi,

I don't understand this problem; is it considered a difficult one or might come across it in a 650 level?

Why can't we deal with it as a regular rate/work problem? Then in 1 hour, Jack can do 1/20 and Tom 1/25..I don't know how to proceed though. I would grealy appreciate any help
Top
Join the discussion
Log in to postLogin with Googleuse password
QUOTE IN REPLY
Post new topic Post Reply
• Page 1 of 1