Question 975461
Fraction of car washed in a minute

(1/6) +(1/8)= (1/x)
Multiply all by 24x

4x+3x+24
7x=24
x=24/7


it will take 1/(24/7) minutes  or 7/24 minutes

Together, they can do it in (1/6)+(1/8)= 7/24 minutes.  This avoids the inversion with division.