Ram starts working on a job and works on it for 12 days and completes

Question

Ram starts working on a job and works on it for 12 days and completes 40% of the work. To help him complete the work, he employs Ravi and together they work for another 12 days and the work gets completed. How much more efficient is Ram than Ravi?

A. 50%
B. 100%
C. 125%
D. 200%
E. 250%

A. 50%
B. 100%
C. 125%
D. 200%
E. 250%

CrackverbalGMAT · Answer

Ram does 40% = 2/5th of the work in 12 days

To complete the work, time taken =  \frac{1 * 12}{\frac{2}{5}} = 30  days

The remaining work is 60% = 60 /100 = 3/5th of the work

Working together they finish 3/5th of the work in 12 days

Therefore to do the complete work =  \frac{1 * 12}{\frac{3}{5}} = 20  days

Work done by Ram in 1 day = 1/30

Let Ravi take x days to finish the work. Work don by Ravi in 1 day = 1/x

\frac{1}{30} + \frac{1}{x} = \frac{1}{20}

\frac{1}{x} = \frac{1}{20} - \frac{1}{30} = \frac{3 - 2}{60} = \frac{1}{60}

Ravi takes 60 days to complete the work which is twice the time Ram takes

Ram is 100% more efficient than Ravi

Option B

Arun Kumar

CEdward · Answer

Here is a slight twist on the way that Arun did it.

If we know 40% was done in 12 days, then the rate of Ram is...
R = (10/3%)/1 day

Since there is 60% of the work left and it took 12 days for both of them to do it, we can set up this equation
(10/3%)/1 day x 12 days + (x) x 12 days = 60% <---Where x is the rate of his Ravi
x = 5/3

Now, let's divide their rates

5/3 : 10/3 = 1:2

Comparing their individual rates we can see that Ram is twice as fast as Ravi. i.e. he is 100% more efficient.

GMAT700SSE · Answer

I solved it that way:

Given that:
0,4W=12*RateRam
0,6W=12*(RateRam + RateRavi)
-> 0,6W=12*RateRam + 12*RateRavi
now we plug the first equation in there to get:
0,6W=0,4W + 12*RateRavi
0,2W = 12*RateRavi

So now we know that Ram completes 2x the work of Ravi in the same time so he is 100% more efficient

MagnusSamIBA · Answer

Ram works 40% in 12 days
He continues working for another 12 days with Ravi → Ram does another 40%
Total work done in those 12 days = 60%
So Ravi must have done the remaining 20% in 12 days

That means:

Ram does 40% in 12 days

Ravi does 20% in 12 days

So Ram is twice as efficient as Ravi
→ Ram is 100% more efficient than Ravi

Answer: (B) 100%

ravi1522 · Answer

Hello ,
AS ram take 12 days for 40% so he will take 30days for 100%
As when they work together that is 60% work the we can calculate the rate of Ravi 
0.60=(1/30+1/R)*12

so we will get rate as 1/60 it means Ravi will take total 60 days to complete work

so ram is (60-30)/30 *100= 100% more efficient 
Hence option B is correct

Ram starts working on a job and works on it for 12 days and completes

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