Thread: Money problems

Can you please help me solve questions 18 and 20 by using substitution or elimination method.
http://img230.imageshack.us/img230/4372/mathyv1.jpg
Thanks

Originally Posted by dgolverk

Can you please help me solve questions 18 and 20 by using substitution or elimination method.
http://img230.imageshack.us/img230/4372/mathyv1.jpg
Thanks

I don't know about anyone else but I can't read the text in your jpg.

RonL

here are the questions:
1)You are starting a business that sells air filters for homes. Your startup costs for the business are $1250 and each air filter kit costs $40.
If you sell the filters for $60, how many must you sell to break even?

2)If you buy 7 hmaburgers and 3 slices of pizza from Sizzler, you get $1 change from $20 bill. If you buy 8 hamburgers and 2 slices of pizza, you get $0.50 back from a $20 bill. How much change would you get from a $20 bill if you bought 3 slices of pizza and 5 hamburgers?

Thanks again!

Originally Posted by dgolverk

here are the questions:
1)You are starting a business that sells air filters for homes. Your startup costs for the business are $1250 and each air filter kit costs $40.
If you sell the filters for $60, how many must you sell to break even?

I will use "substitution" since I believe that's what your teacher wants...

The amount of money you pay equals $1250 plus $40 per filter.

y=the amount of money
x=filters

Thus you have equation: y=40x+1250

The amount of money you make is equal to $60 per filter: y=60x

To braek even, the amount of money you make must equal the amount of money you spent, thus: 40x+1250=60x

now subtract both sides by 40x: 1250=20x

Now divide both sides by 20: 62.5=x

So you need to sell 62.5 filters to break even, which you can't do, so you sell 30 filters to break even.

2)If you buy 7 hmaburgers and 3 slices of pizza from Sizzler, you get $1 change from $20 bill.

7h+3p=19
Solve for p to get: p=(19-7h)/3

If you buy 8 hamburgers and 2 slices of pizza, you get $0.50 back from a $20 bill.

8h+2p=19.5

Solve for p to get: p=(19.5-8h)/2

Substitute: (19-7h)/3=(19.5-8h)/2

solve for h, then substitute that value into one of the equations to find the price of hamburgers, than subtract the price of 3 slices of pizza and 5 hamburgers from 20.

Thanks!