Answer:
(A) All three spend all their time washing cars
In 10 hours Rajiv will wash 10 cars, because he can wash 1 car per hour.
Yakov will also wash 10 cars because he can wash 1 car per hour.
And, Charles will wash 20 cars because he can wash 2 cars per hour.
(B) All three spend half their time on each activity.
In 5 hours, Rajiv will mow 10 lawns, and wash 5 cars.
Yakov will mow 5 lawns and wash 5 cars.
And Chalres will mow 5 lawns and wash 10 cars.
(C) Rajiv spends half his time on each activity, while Yakov only washes cars and Charles only mows lawns.
Rajiv will mow 10 lawns and wash 10 cars.
Yakov will wash 10 cars.
And Charles will mow 10 lawns.
(D) Identify the opportunity cost of washing cars for each worker.
For Rajiv, the opportunity cost of washing 1 car is not mowing 2 lawns.
For Yakov, the opportunity cost is not mowing 1 lawn.
For Charles, the opportunity cost is not mowing half a lawn.