Question 1033132

A chemistry experiment requires that a vacuum be created in a chamber. A small vacuum pump requires 15 seconds to evacuate the chamber. Working together, the chamber can be evacuated in 4 sec. Find the time required for the larger vacuum pump working alone to evacuate the chamber.
<pre>With larger taking L seconds, we get:
{{{1/15 + 1/L = 1/4}}}
4L + 60 = 15L ------- Multiplying by LCD, 60L
4L - 15L = - 60
- 11L = - 60
L, or time larger takes, alone = {{{(- 60)/(- 11)}}}, or {{{highlight_green(matrix(1,2, 5&5/11, seconds))}}}