Hi,

I am stuck on this questions:

A certain tank can be filled by two pipes in 80 minutes. The larger pipe by itself can fill the tank in 2 hours less than the small pipe by itself. How long does each pipe take to fill the tank on it's own?

My attempt so far:

Large pipe = l

Small pipe = s

time = t

Hence:

(Large pipe + Small pipe) x time = 1 filled tank

Since

I still have the s in the answer? how am i suppose to calculate t?