# Bob can wash a car in 6 minutes. Bill can wash a car in 8 minutes. How long will it take if Bob and Bill wash a car together?

$\frac{24}{7} \text{minutes}$
Bob can wash a car in 6 minutes. So in one minute washes $\text{1/6}$ of a car.
Bill the same washes $\text{1/8}$ of a car in a minute. Both wash the car in $\frac{1}{x}$ minutes. But
1/6+1/8=1/x=> 24x*1/6+24x*1/8=24x*1/x=>4x+3x=24=> 7x=24=>x=24/7"minutes"