Jack and John undertake a piece of work for $6000. Jack alone could do

Question

Jack and John undertake a piece of work for $6000. Jack alone could do the work in 6 days and John in 8 days. With the assistance of a Tom, they finish it in 3 days. How much money does Tom get paid?

A. $750
B. $1000
C. $820
D. $2000
E. $1200

divyadna · Answer

Posted from my mobile device

ThatDudeKnows · Answer

Is there some piece of information that would make this question really easy? What if we knew what the job was and it just happened to use a number that's really easy to work with given the other numbers in the question? Awesome, that makes this a Hidden Plug In question (there's no explicit variable, but there's something we can make up). Let's say the job is complete 48 GMAT questions.

Jack can do it in 6 days, so he can do 8 questions per day.
John can do it in 8 days, so he can do 6 questions per day.
Jack and John together can do 14 questions per day.
Jack, John, and Tom can do 48 questions in 3 days, so all of them together can do 16 questions per day.
All three do 16 per day and J+J do 14 per day, so Tom does 2 per day.
Tom does 2 out of every 16, so 1/8. 1/8th of $6000 is $750.

Answer choice A.

ThatDudeKnowsHiddenPlugIn
ThatDudeKnowsRates

GMATWhizTeam · Answer

Let the total work done be the LCM of 8, 6 and 3 i.e. 24 units.

Jack can do 24 units in 6 days, so Jack’s rate of doing work = 4 units per day
John can do 24 units in 8 days, so John’s rate of doing work = 3 units per day

With the assistance of Tom, 24 units was completed in 3 days; therefore, combined rate of Jack, John and Tom = 8 units per day.
Therefore, Tom’s rate of doing work = 1 unit per day

Since all three of them worked for all 3 days, the distribution of money can be done in the ratio of their respective rates.
Tom’s share =  \frac{1 }{ (1 + 3 + 4)}  * 6000 =  \frac{1 }{ 8}  * 6000 = 750

The correct answer option is A.

bumpbot · Answer

Automated notice from GMAT Club BumpBot: 

A member just gave Kudos to this thread, showing it’s still useful. I’ve bumped it to the top so more people can benefit. Feel free to add your own questions or solutions.

 This post was generated automatically.

Jack and John undertake a piece of work for $6000. Jack alone could do

Prep Toolkit

Top 5 GMAT Debrief Videos

615 to 715 in 15 Days (Ria's Strategies)

More than Quant/Verbal Abilities: Speed vs. Accuracy

745 with Only Self-Prep and GMAT Club

From 555 to 765: 210-point Improvement

Perfect 805 Score Debrief by Julia

My Rewards

GMAT Problem Solving (PS) Questions

Jack and John undertake a piece of work for $6000. Jack alone could do

Prep Toolkit

615 to 715 in 15 Days (Ria's Strategies)

More than Quant/Verbal Abilities: Speed vs. Accuracy

745 with Only Self-Prep and GMAT Club

From 555 to 765: 210-point Improvement

Perfect 805 Score Debrief by Julia

My Rewards