Question

A, b and c together can do a piece of work in 15 days, b alone can do it in 30 says and c alone can do it in 40 days.In how many days will a alone do the work?

Answer 1

Answer:

a alone do the work in 120 days

Step-by-step explanation:

A, b and c together can do a piece of work in 15 days

A, b and c 1 day work = 1/15

b alone can do it in 30 days

b's 1 day work = 1/30

c alone can do it in 40 days

c's 1 day work = 1/40

Let say a alone can do it in a days

a's 1 day work = 1/a

a b c's together 1 day work

= 1/a + 1/30 + 1/40 = 1/15

=> 120/a  + 4 + 3 = 8      ( multiplying by 120 both sides)

=> 120/a = 1

=> a = 120

so a alone will do in 120 Days