Question

Two pipes fill a storage tank in 9 hours. The larger pipe fills the tank three times as fast as the smaller one. How long would it take the larger pipe to fill the tank alone

Answer 1

let the smaller pipe rate be v
so the larger will be 3v

(v+3v) * 9 = 1
36v = 1
v=1/36

so in order to find t the time that it would take for the larger pipe all we haveto do is
3v * t = 1
you plug here the v that we found up there

Answer 2

21 hours?

Answer 3

or 18. @Coolsector

Answer 4

lets do this together :
3v*t=1
3 * (1/36) * t = 1
(1/12) * t = 1
t = 12