Question

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Question 9 of 10
Richard and Spiro are plumbers. For a big job at Mr.
White's house, Richard said he would charge $45
per hour. Spiro said he would charge $150 for parts
and $35 per hour of work.
After how many hours of work would both plumbers
charge the same amount of money for the job?

Answer 1

15 hours of work would both plumbers charge the same amount of money for the job.

Explanation:

Let us assume the number of hours Richard works = m

Per hour charge = $45

So, the charge for working m hours = m x $45 = 45 m ....... (1)

Let us assume the number of hours Spiro works = m

Per hour charge = $35

So, the charge for working m hours = m x $35 = 35 m

Also, the charge for parts = $150

So, total amount Spiro charges = Cost for m hours + Charge for parts

= 35 m + $150 ...... (2)

Now, for m hours as they charge the SAME AMOUNT.

⇒ From (1) and (2), we get

45 m = 35 m + $150

or, 45 m - 35 m = 150

or, 10 m = 150

⇒ m = 150/10 = 15

or, m = 15

Hence, 15 hours of work would both plumbers charge the same amount of money for the job.