Question 426390
"The larger pipe working alone can fill the tank in 6 hrs less than the smaller one" ___ L = s - 6


each pipe fills a FRACTION of the tank , based on the individual rates
___ the fractions add to one , the WHOLE tank


(4 / L) + (4 / s) = 1


substituting for the value of L ___ [4 / (s - 6)] + (4 / s) = 1


multiplying by [s(s-6)] ___ 4s + 4s - 24 = s^2 - 6s


0 = s^2 - 14s + 24


factoring ___ 0 = (s - 2)(s - 12)


s - 2 = 0 ___ s = 2 ___ this value is not realistic because L is 6 less than s , and L is not negative


s - 12 = 0 ___ s = 12