Question

If ramesh, suresh & harish can do a piece of work in 15, 10 & 6 days resp. how long will they take it if all of them work together?

Answer 1

Ramesh=1/15
Suresh=1/10
Harish=1/6
Now,
Ramesh, Suresh and Harish will take=1/15+1/10+1/6=2+3+5/30=10/30=1/3 days

Answer 2

Answer:

When all the three are working together, then the work will be completed in 3 days.

Step-by-step explanation:

Given ramesh, suresh & harish can do a piece of work in 15, 10 & 6 days respectively.

If ramesh complete the work in 15 days, then in 1 day he do $\frac{1}{15}$ of the work.

If suresh complete the work in 10 days, then in 1 day he do $\frac{1}{10}$ of the work.

Similarly, If harish complete the work in 6 days, then in 1 day he do $\frac{1}{6}$ of the work.

If all the three are working together, then the work done in 1 day will be

$=\frac{1}{15} +\frac{1}{10} +\frac{1}{6}$

L.C.M. of 15, 19 and 6 is 60.

$\frac{1}{15} +\frac{1}{10} +\frac{1}{6}=\frac{4\times 1+6\times 1+10\times 1}{60}$

$=\frac{4+6+10}{60}$

$=\frac{20}{60}=\frac{1}{3}$

Therefore, when all are working together, then the work is completed in 3 days.