number problem

Question

Brian is working his way through school. He works two part-time jobs for a total of 32 hours a week. Job A pays $6.40 per hour, and Job B pays $7.20 per hour. How many hours did he work at each job the eek that he made $220.80

Answer 1

A = hours on job A

B = hours on job B

 

A + B = 32, or A = 32 - B

 

6.4A = money from job A

7.2B = money from job B

 

6.4A + 7.2B = 220.8             substituting the above

 

6.4(32 - B) + 7.2B = 220.8

204.8 - 6.4B + 7.2B = 220.8

204.8 + 0.8B = 220.8

0.8B = 16

B = 20

 

He worked 12 hours on job A and 20 hours on job B.

 

Check:

12(6.4) + 20(7.2)

76.8 + 144

220.80