Question 143539
Susan's rate + Joan's rate = Rate working together
In words:
(1 golfball / .016 hrs) + (1 golfball / .025 hrs) = (x golfballs / 1 hrs)
{{{1/.016 + 1/.025 = x}}}
multiply both sides by {{{.016*.025}}}
{{{.025 + .016 = (.016*.025)*x}}}
{{{.0004x = .041}}}
{{{x = 102.5}}}
They are recovering 102.5 golfballs per hr working together
check answer:
{{{1/.016 + 1/.025 = x}}}
{{{62.5 + 40 = 102.5}}}
{{{102.5 = 102.5}}} 
OK