Question 198212
In words:
sally's rate of painting is (1 house) / (4 hours)
John's rate of painting is (1 house) / (6 hours)
If I add the rates, I get the rate of both
working together
{{{1/4 + 1/6 = 1/x}}}
Multiply both sides by {{{12x}}}
{{{3x + 2x = 12}}}
{{{5x = 12}}}
{{{x = 2.4}}}
Working together, they can paint the house in 2.4 hours