word problem linear system

Question

John works 2 jobs, one job pays $10 per hour and the other pays $12 per hour. If he works a total of 25 hours in one week and earns $278 in total, how many hours does he work at each job?

Answer 1

h represents the hours at $12

25 - h represents the hours at $10

 

12h + 10(25 - h) = 278

 

Can you solve for ha and answer? 

Answer 2

X is the number of hours worked at the first job

Y is the number of hours worked at the second job

 

X+Y = 25 <--- total of 25 hours worked

 

10X + 12Y = 278  <--- total earned is $278

 

Y = 25 - X

 

10X + 12(25 - x) = 278

 

10X + 300 - 12x = 278

 

-2x + 300 = 278

 

-2x = -22

 

x = 11

 

Y = 14

 

11 hours at the first job and 14 hours at the second job

 

CHECK: 11*$10 + 14*$12 = $110 + 168 = $278