Question

K, L and M can do a piece of work in 20, 30 and 60 days respectively. In how many days can K do the total work if he is assisted by L and M on every third day ?
A) 15 days
B) 13 days
C) 12 days
D) 10 days

Answer 1

LCM of 20, 30 and 60 is 60

So we will take total work to be 60 units.

A = 60/20 = 3 units/day

B = 60/30 = 2 units/day

C = 60/60 = 1 units/day

Now A is working two days alone and on third day B and C are joining him and this goes on and on until work is done.

Day 1 = A’s work = 3 units

Day 2 = A’s work = 3 units

Day 3 = (A + B +C) ‘ s work = 3 + 2 + 1 = 6 units

So this is a set of 3 days in which total 3+3+6 = 12 units work is being done.

Now to complete 60 units, 60/12 = 5 such sets of 3 days are needed.

5 sets of 3 days means 5*3 = 15 days

Answer 2

K, L and M can do a piece of work in 20, 30 and 60 days respectively. In how many days can K do the total work if he is assisted by L and M on every third day ?
A) 15 days✔
B) 13 days
C) 12 days
D) 10 days



ĀNSWĒR ⏬⏬

A. 15 days


Thanks ✌✌


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