Question

Rosemary works two part-time jobs while attending college. During the day she works at the college bookstore and earns $8.25 per hour. In the evening she delivers pizza for Papa Gino's, earning $9.25 per hour. If Rosemary earned $247 last week from working a total of 28 hours, find how many hours she worked at Papa Gino's last week.

Answer 1

Rosemary worked 12 hours at the bookstore and 16 hours driving around for pizza delivery.

Explanation:

Let x be the number of hours spent working at the bookstore where she makes 8.25 an hour. Her pay from the bookstore is in total, 8.25x.

Likewise, let's let y = the number of hours working at the pizza place. Her total pay there would be 9.25y.

Her all together over all pay would be:

bookstore$ + pizza$

8.25x + 9.25y

= 247

8.25x + 9.25y = 247

here is one equation. It tells us her total pay from both jobs is 247.

Also, her hours totaled 28. So,

x + y = 28

Solve the system of equations:

8.25x + 9.25y = 247

x + y = 28

You could use substitution or elimination. If you are learning matrices or a graphing program you could use that.

Here is the substitution work.

x + y = 28

y = 28 - x

8.25x + 9.25y = 247

substitute. y = 28-x

8.25x+9.25(28-x)=247

use distributive property.

8.25x+259 - 9.25x=247

combine like terms.

259 - x = 247

subtract 247, add x

12 = x

This means that Rosemary worked 12 hours at the bookstore. And since 28 - 12 = 16.

She works 16 hours at the pizza delivery

12 + 16 is 28, the number of hours she worked.

Also, 8.25(12)+9.25(16)

= 99 + 148

= 247

So these number check out.