Question

Ronnie charges his customers a flat fee of $25 to fix a computer. Then, he charges $30 for each hour he spends working on the computer. If his first job cost $175, how many hours did he spend working?

Answer 1

7.5

Step-by-step explanation:

Ronnie charges $25 plus $20 per hour. This means that he made the following depending on how many hours he spent on it:

Hours Dollars

0 25 = 25 + 0(20)=25

1 25+20 = 25 + 1(20)=45

2 25+20+20 = 25 +2 (20)=65

3 25+20+20+20 = 25 +3 (20)=85

4 25+20+20+20+20 = 25 +4 (20)=105

5 25+20+20+20+20+20 = 25 +5 (20)=125

......

n 25+n(20)=175

To find how many hours he worked for $175 we solve the equation using inverse operations:

25+n(20)=175

25-25+n(20)=175-25

n(20)=150

n= 7.5 hours

Answer 2

Ronnie spent 5 hours working.

Explanation:

From the information given, the total cost of the job is equal to the flat fee plus the result of multiplying the cost per hour for the number of hours which is:

c=25+30x, where:

c is the total cost of the job

x is the number of hours

Now, you can replace c with 175 and solve for x:

175=25+30x

175-25=30x

150=30x

x=150/30

x=5

According to this, the answer is that Ronnie spent 5 hours working.