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 smaller pipe by itself. How long does each pipe take to fill the tank on its own?

Question

anonymous · Answer

80 minutes = 1 1/3 hour

lgbasallote · Answer

actually it's a work problem where 1/x + 1/y = 1/t where t = total time working together

anonymous · Answer

ooh yeah. . my bad. .

lgbasallote · Answer

i tried solving it...my brain hurt =)))

anonymous · Answer

let x= smaller pipe
     y= bigger pipe

so, equations will be,

(1)  1/x +1/y = 1 1/3
(2)   y = x-2

lgbasallote · Answer

actualy 1/x + 1/y + 1/4/3

anonymous · Answer

i think it's 4/3 or 1 1/3, not 1/4/3

dumbcow · Answer

$$\frac{1}{x}+\frac{1}{x-2} = \frac{3}{4}$$
$$\frac{2(x-1)}{x(x-2)} = \frac{3}{4}$$
$$8x-8  = 3x^{2}-6x$$
$$3x^{2} -14x+8 = 0$$
$$(3x-2)(x-4) = 0$$
x = 4

so it takes larger pipe 2 hrs and smaller pipe 4 hrs

anonymous · Answer

That's what the book says, how did you get from step 1 to step 2

anonymous · Answer

Don't worry I got it now

dumbcow · Answer

combined fractions....ok:)

anonymous · Answer

In step one, why is it equal to 3/4 shouldn't it be 4/3

dumbcow · Answer

each fraction represents the rate it takes to fill up the tank, T/hr
it took 4/3 hr so rate is 1/(4/3) = 3/4 tanks per hr

anonymous · Answer

Ahh... Thanks

dumbcow · Answer

welcome