A group of 4 junior lawyers require 5 hours to complete a legal resear

Question

Tough and Tricky questions: Work/Rate Problems.

A group of 4 junior lawyers require 5 hours to complete a legal research assignment. How many hours would it take a group of three legal assistants to complete the same research assignment assuming that a legal assistant works at two-thirds the rate of a junior lawyer?

A) 13
B) 10
C) 9
D) 6
E) 5

Kudos for a correct  solution .

Source: Chili Hot GMAT

sunaimshadmani · Accepted Answer

Convert rate of assistant to junior lawyer,
Assistant = 2/3 Jr.lawyer,
so 3 assistants = 2/3 * 3 = 2 junior lawyer.
Now 4 lawyers completed the job in 5hrs so 2 of them will complete in 5*2 = 10hrs

PareshGmat · Answer

Answer = B) 10

Rate of a Lawyer  = \frac{1}{5*4} = \frac{1}{20}

Rate of a assistant  = \frac{1}{20} * \frac{2}{3} = \frac{1}{30}

Rate of 3 assistants  = 3 * \frac{1}{30} = \frac{1}{10}

Time required by3 assistants = 10

intheend14 · Answer

Assuming that all junior lawyers work at the same rate, we can formulate the expression of 4*1/x (representing the 4 lawyers working together) and this equals 1/5 (reciprocal of the time it takes them together). Solving for x yields 20 hours (the time it takes one lawyer working alone). Since the assistants work at 2/3 the rate, it takes each of them 20*3/2=30 hours individually. For 3 of them working together, it takes 3*1/30 = 1/10, which is the reciprocal of 10 hours for them working as a group.

Choice B

Choice B

Ankur9 · Answer

one hr work of 4 lawyers is 1/5
then one hr work of 1 lawyer will be 1/20
given that assistant works at two-thirds the rate of a junior lawyer
therefore in one hr an assistant will complete 2/3 of 1/20 i.e 1/30 of work
then one hr work of a group of 3 assistants will be 3* 1/30 = 1/10
thus a group of 3 assistant will complete the work in 10 hours

amitshri15 · Answer

Work = worker * time = 4*5 =20
20 = (2/3)*3 * t => t=10

Answer is B.

pacifist85 · Answer

Unless my line of reasoning is not correct, this one was actually extremely easy, if you just notice this:

# of people times the # of hours:
4*5 = 20 --> 4 lawyers do 20 "works" in 5 hours.
3*10/3 = 30/3 = 10 --> 3 assistants do 10 "works" in 10/3 hours (2/3*5= 10/3)

So, since the amount of work the assistants do is half the work the lawyers do, the time will be double, so  ANS B

rsh12 · Answer

4J.L ---- 5hrs ------ 1/20 (per hr per J.L)

1/10 ------ (per hr per L.A)

Therefore 10 hours in total.

longhaul123 · Answer

So there are 4 junior lawyers and they work for 5 hours, therefore the total work is of 20 units (number of men *number of hours)
Now the rate of the junior lawyer is total work / total time = 20/5=4 units / hour
Now the rate of the legal assistant is 2/3 of the rate of the junior
Therefore, 2/3 (4)=8/3 is the rate of the legal assistant 
Is my method of calculation wrong and also can someone help me know as to where am I going wrong in my concepts. Thanks in advance

philipssonicare · Answer

numberofpeople_1 · time_1 · rate_1 = numberofpeople_2 · time_2 · rate_2  (use of titles 'lawyer' and 'legal assistant' only help for clarity, they don't change the set up of the equation)
 4(people)·5(hours)·r= 3(people)·t(hours)·\frac{2r}{3} 
Can cancel the units and  r  as they are the same both sides
 4·5=3·t·2/3 
 10=t

Abhishek009 · Answer

5*\frac{4}{3}*\frac{3}{2}=10 , Answer must be (B) 10

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A group of 4 junior lawyers require 5 hours to complete a legal resear

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