Peppy Pets charges a flat fee of $15 plus $3 per hour to keep a dog during the day. Happy Hounds charges a flat fee of $21 plus $1 per hour. For how many hours is the total fee charged by the companies the same? a) 4 hours b) 5 hours c) 2 hours d) 3 hours

d) 3 hours.

Step-by-step explanation:

Let x be the required number of hours for which the total fee charged by the companies the same.

Given: Peppy Pets charges a flat fee of $15 plus $3 per hour .

So Total charge = 15+3x  ( in dollars)

Happy Hounds charges a flat fee of $21 plus $1 per hour.

So Total charge = 21+x  ( in dollars)

When the total charge for both companies are the same, then

Hence, the correct option is d) 3 hours.

step-by-step explanation: