Let x be the amount of peak time and y be the amount of off-peak time.
30x + 12y = 876.00
x + y = 40
Lets multiply the second equation by 12.
12x + 12y = 480
We can now subtract the two equations from each other to cancel out the y term.
30x + 12y = 876
12x + 12y = 480
18x + 0 = 396
Next, we can solve for x.
18x = 396
x = 22
Lastly, we can plug this value into one of the equations to solve for y.
22 + y = 40
y = 18
So, the number of peak hours was 22 and the number of off-peak hours was 18. The answer is C.