Question 1197446
<pre>
                       TIME       RATE

smallhose                x       1/x

bighose                  x-6     1/(x-6)

combined                  4      1/4
</pre>
Combined-rate
{{{1/x+1/(x-6)=1/4}}}

-

{{{x-6+x=(x(x-6))/4}}}

{{{2x-6=(x^2-6x)/4}}}

{{{8x-24=x^2-6x}}}

{{{x^2-14x+24=0}}}

{{{(x-12)(x-2)=0}}}------------ x can only be 12.