The correct question is:
At his regular hourly rate, Don had estimated the labour cost of a repair job as $336 and he was paid that amount. However, the job took 4 hours longer than he had estimated and, consequently, he earned $2 per hour less than his regular hourly rate. What was the time Don had estimated for the job, in hours?
(A) 28
(B) 24
(C) 16
(D) 14
(E) 12
Answer:
24 hours
Explanation:
Amount paid (S) = Hourly rate(h) * Time taken(t)
So ideally 336= ht
In reality
Don spent 4 hours extra= t+4
And earned $2 less per hour= h-2
So 336= (h-2)*(t+4)
Combining the two equations
336= ht= (h-2)*(t+4)
Open the brackets
ht= ht+ 4h- 2t -8
Rearranging
ht- ht + 2t= 4h-8
t = (4h-8)/2 = 2h-4
In formula t= 2h- 4, substitute the given options of t to get h.
The pair that will give ht= 336 is the correct one.
Using 24 hours
24= 2h-4
24+4= 2h
28/2= h
14= h
So for t= 24, h=14
Check in formula ht= 336
24*14= 336
So 24hours is the correct answer.
