Question 452536
Raul can plumb a house in {{{48hr}}}.....->........rate is {{{1/48}}}

Mira can plumb a house in {{{36hr}}}.....->........rate is {{{136}}}

now find the rate if they work together:


{{{1/48 + 1 / 36 = 1/x}}}........ multiplying each term by common denominator {{{144}}}, you got


{{{1*144/48 + 1*144 / 36 = 1*144/x}}}


{{{1*3 + 1*4 = 144/x}}}

{{{7= 144/x}}}

{{{7x= 144}}}

{{{x= 20.571428571428571428571428571429}}}.which is approximately

{{{x= 21h}}}