Question

if one pipe can fill a tank in 1 1/2 hr and another pipe can fill the same tank in 45 min , how long will the two pipes take to fill the tank together​

Answer 1

One pipe takes 45 minutes - rate: 1/45

The other takes 30 minutes - rate: 1/30

1/45+1/30=1/x

(2+3)/90 [45*2=90; 90×3=90]

5/90≈1/18

1/18=1/x

So x = 18 [cross multiply]

So, it takes them 18 minutes to fill it together