Question 404875
You are adding rate:
(1 tub filled w/cold faucet)/(min to fill tub) + (1 tub filled w/hot faucet)/ (min to fill tub) = (1 tub filled)/(x min with both faucets open)
{{{1/10 + 1/12 = 1/x}}}
Multiply both sides by {{{60x}}}
{{{6x + 5x = 60}}}
{{{11x = 60}}}
{{{x = 60/11}}} min