Question

if a and b together complete the work in 10 days B and c together complete the work in 15 days and CA together complete the work in 12 days in how many days they do it separately

Answer 1

(a+b)'s 1 day job = 1/10

(b+c)'s 1 day job = 1/15

(c+a)'s 1 day job = 1/12

Adding the three equations we get -

2(a+b+c)'s 1 day job = 1/10+1/15+1/12= 15/60 = 1/4

or (a+b+c)'s 1 day job = 2*1/4

Hence time taken by all to complete the job = 2/4 = 1/2 days