Filling a TankDate: 12/19/2002 at 05:58:03 From: Shabnam Subject: Filling a tank A tank is filled by two pipes. The smaller pipe alone will take 24 minutes longer than the larger pipe and 32 minutes longer than when booth pipes are used. How long will each pipe take to fill the tank alone? Date: 12/19/2002 at 09:44:12 From: Doctor Ian Subject: Re: Filling a tank Hi Shabnam, This is a new twist on an old problem; see the Dr. Math FAQ: Working Together http://mathforum.org/dr.math/faq/faq.working.together.html The standard formula is that if the first entity takes A units of time,and the second takes B units of time, then together they take A * B ----- A + B units of time. If the small pipe takes x minutes to fill the tank, then the larger one takes (x-24) minutes, and the combined time is x * (x-24) ---------- x + (x-24) But this has to be (x-32) minutes, so x * (x-24) ---------- = (x-32) x + (x-24) x(x - 24) = (2x - 24)(x - 32) x^2 - 24x = 2x^2 - 64x - 24x + (24)(32) 0 = x^2 - 64x + (24)(32) Can you take it from here? - Doctor Ian, The Math Forum http://mathforum.org/dr.math/ |
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