Each day, Ted can wax 8 cars or wash 10 cars, and Tom can wax 3 cars or wash 5 cars. What is each man's opportunity cost of washing a car?

1/2

Explanation:

This will lead us to simultaneous equation since there are two person involved doing the same job each day.

For Ted;

Since Ted can wax 8 cars or wash 10 cars in a day. Mathematically, we have

8x + 10w = 1 ... (1)

Where x is for waxing cars, w is for washing cars

Similarly for Tom,

Tom can wax 3 cars or wash 5 cars in a day as well, this gives us;

3x + 5w = 1 ... (2)

Equating 1 and 2, we have;

8x + 10w = 1 ... (1)

3x + 5w = 1 ... (2)

Using elimination method, we will multiply eqn 1 by 3 and eqn 2 by 8 to have;

24x + 30w = 3

24x + 40w = 8

Subtracting eqn 4 from 5 we have;

30w - 40w = 3 - 8

-10w = - 5

w = 5/10

w = 1/2

Therefore each man's opportunity cost of washing a car is 1/2