Question

A built a wall in 10 days,b built the same in 12 days and c can do it in 15 days. Which two of them will combine to do the work in 6 days?

Answer 1

If we hv to build wall in six days we hv calculate to 1/6 per day

A built a wall in one day=1/10

B built a wall in one day=1/12

C built a wall in one day=1/15

I.e. 1/10+1/15=???

That is 1/6

So that A & C built wall in six days

Answer 2

Answer:

a built in a wall =1/10

b built in a wall =1/6

c built in a wall=1/15

we want to 1/6

so that adding 1/10+1/15

=15+10/150=1/6