Question

A can do a piece of work in 24 days and b in 30 days. with help of c, they finish the work in 12
days. in how many days c alone can do the same work?

Answer 1

Step-by-step explanation:

Combine efficiency of work done by a and b = 1/24 + 1/30;

1/a + 1/b = (5+4)/120;

1/a + 1/b = 9/120;

Combine efficiency of a, b and c is = 1/a + 1/b + 1/c;

1/a + 1/b + 1/c = 1/24 + 1/30 + 1/c = 1/12;

Now Putting the value of 1/a + 1/b is above equation we get;

9/120 + 1/c = 1/12;

1/c = 1/12 - 9/120;

1/c = 10-9/120;

1/c = 1/120;

120 days required for c to the work alone.