Question

A and b can fill tank in 5 and 15 hr respectively with help of c can empty a tank in 4 hrs if they open alternatevly base

Answer 1

after lcm of 5 and 15

A=5=3

b=15=1

c=4=15/4

15/4-15/4=15/1/4=60hr is ur answer

Answer 2

tap A fill in 5 hrs

tapB fill in 15 hrs

tab C empty in 4 hrs

so in one hour

water in tank =1/5+1/15-1/4

=12/60+4/60-15/60

=1/60

so in 60 hrs tank is filled