Question 131422
Add their rates of working
( 1 job/4 days) + (1 job/6 days) = (1 job/x days)
{{{1/4 + 1/6 = 1/x}}}
multiply both sides by {{{4*6*x}}}
{{{6x + 4x = 24}}}
{{{10x = 24}}}
{{{x = 2.4}}}
It takes them 2.4 days working together
check:
{{{1/4 + 1/6 = 1/x}}}
{{{1/4 + 1/6 = 1/2.4}}}
multiply both sides by 24
{{{6 + 4 = 10}}}
{{{10 = 10}}}
OK