12. At his regular hourly rate, Don had estimated the labor 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 consequentially he earned $2 less than his hourly rate. What was the price Don had estimated to work? a. $12 b. $14 c. $16 d. $24 e. $28

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.