The electrician arrives at Laura's house to fix her broken furnace. The electrician charges 90 dollars for the first hour and 60 dollars for each additional hour. If the total bill comes to 330 dollars how long will the electrician at Laura's house?

5 hours

Step-by-step explanation:

Electrician got 90 for the first hour from the total bill, thus we can say:

330 - 90 = 240 remaining for remaining hours

$60 per hour, so $240 for how many hours? We divide:

240/60 = 4 hours

So, electrician works 4 hours for 60 per hour = 2 * 6 = 240

and 1 hour for 90 (first hour) = 1 * 90 = 90

Total Bill is 240 + 90 = 330 {exactly what we have}

So we have checked and back-worked our problem to get electrician's total hours of work:

1 + 4 = 5 hours