Answer:
Number of hours= (Total earnings+ Total costs)/$15
Mika worked 18 hours
Step-by-step explanation:
Mika´s earnings function is:
Total earnings= Total Payment-Total costs
The total payment depends on the number of hours Mika took to pint the neighbor's fence:
Total earnings= $15x-Total costs
Now we transform this equation to know the number of hours worked:
Total earnings+Total costs= $15x
(Total earnings+ Total costs)/$15=x
x= $174+$96/$15
x= 18
Mika worked 18 hours