A plumber charges a base fee of $ 60, and then each hour of work costs $ 15. Yesterday Joe hired the plumber to fix his sink, at a total cost of $ 240. How many hours did the plumber work 3.75 hours 4 hours 12 hours 16 hours

12 hours

Step-by-step explanation:

Step one:

given data

base fee= $60

charge per hour= $15

let the number of hours the plumber work be x

the linear function for the charge is the equation of line.

that is y=mx+c

Step two:

given that y=$240

240=15x+60

240-60=15x

180=15x

divide both sides by 15 we have

x=180/15

x=12

The number of hours is 12

48 / 6 = x

in this case, x will equal the amount of money in each card!

x therefore will be 8.

trent had $8 in each birthday card.