Given:
Sheila can wash her car in 15 minutes. Bob takes time twice as long to wash the same car.
Required:
Find the time they take both together.
Explanation:
Sheila can wash her car in 15 minutes.
Work done by sheila in a minute =
[tex]\frac{1}{15}\text{ }[/tex]
Bob takes time twice as long to wash the same car. He washes the car in 30 minutes.
Work done by Bob in a minute
[tex]=\frac{1}{30}[/tex]
If they work together let them take time x per minute.
[tex]\frac{1}{15}+\frac{1}{30}=\frac{1}{x}[/tex]
Solve by taking L.C. M.
[tex]\begin{gathered} \frac{2+1}{30}=\frac{1}{x} \\ \frac{3}{30}=\frac{1}{x} \\ \frac{1}{10}=\frac{1}{x} \\ x=10\text{ minutes.} \end{gathered}[/tex]
If they work together they will take 10 minutes.
Final Answer:
Sheila and Bob wash the car together in 10 minutes.
