Three men A, B and C working together can do a work in 30 da

For A: one cycle is 4 days. In 40 days there are 40/4=10 cycles. In each cycle A works for 3 days, thus in 40 days A does 3*10=30 units.

Hi bunnel,

I am not able to understand how you took the cycles part

Test the options. In 40 days:
A will do 10*3=30 units (10 complete cycles).
B will do 5*5+5=30 units (5 complete cycles and 5 days of work).
C will do 4*7=28 units (4 complete cycles).

Can you please elaborate

Hi Bunnel,

How did you got this B will do 5*5+5=30 units (5 complete cycles and 5 days of work).

40/7=5.714 so i understood that he completed 5 cycles so are you trying to say that the statement is like this (35/7)5 + (40-35)

5 complete cycles is 35 days and then 5 days of work!

Sorry, but this is a confusing and poorly-written question. You can get an answer that isn't even on the list if you interpret a certain way. The question doesn't specify whether this work schedule is cyclical or it just happened one time.

I interpreted it as if it happened one time:

Each worker completes 1/90 of a work per day individually.

Days 1-3: All three work together so they complete 3*(3/90) = 9/90
Day 4: A takes a break, B and C work together so they complete 1*(2/90) = 2/90
Day 5: All three work together again so they complete 1*(3/90) = 3/90
Day 6-7: Worker B takes a break so they complete 2*(2/90) = 4/90
Day 8-10: Worker C takes a break, A and B work together and complete 3*(2/90) = 6/90

So for the first 10 days they complete a total of 9 + 2 + 3 + 4 + 6 = 24/90 of the work, which means that they have an additional 66/90 to complete.

This is where the question breaks down. You can assume that they will go through the same cycle again OR you can assume that they will work together for the remainder of the time. If they work together they must complete (3/30)*x = 66/90 works. If you solve for x, you get x = 22. Add that to the first 10 days and the total is 32, which is not a choice.

Problem took me 3 minutes, not because it was difficult, there was just a ton of drudgery as far as adding everything.

I did this question in same way till i got 24/90.
Till this point I know that 24/90th work was completed in 10 days. A, B and C followed the same schedule.
then 1 work will be completed in 10*90/24 and I got 37.5 days.

Need expert support for this approach. Where I am wrong!

Total work is 90 man days
Taking first option 39 days
A work in 39 days = 3/4×36+ 3= 30
B work in 39 days = 5/7×35+ 4= 29
C work in 39 days = 7/10×30 +7= 28
Remaining work = 3 man days
Only B will work on 40th day
A and C will work on 41st day to complete rest of 2 man days job.
So answer is exactly 41 days.

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