A mechanic can install carburetors in cars every hours. At that rate, how long will it take the mechanic to install carburetors in cars?
A. hr min
B. hr min
C. hr min
D. hr min
E. hr min
This is a work/rate problem. It is further complicated by the use of two types of units – hours in the question and a combination of hours and minutes in the answer.
I suggest you remember that every 15 minutes is 1/4 or 0.25 of an hour and 20 minute are one third of an hour.
Now lets get to work…
Our mechanic installs carburetors in 3 cars every 4 hours. It takes him then (without lunch breaks etc.) one hour and 20 minutes (a third) to install a carburetor in one car. Times five will give us 5 hours + 5X1/3 of an hour or another hour and forty minutes. Altogether 6 hours and forty minutes.