application problem

Question

There are 100 candy bars. Some cost 75 cents; some cost $1. The total cost was $80. How many $1 bars? I have to write an equation

Answer 1

Hi Liz,

 

Let X = the number of 75 cent bars

 

Let Y = the number of $1 bars

 

There are 100 candy bars, so X + Y = 100

 

The total cost was $80 so .75X + 1Y = 80

 

Substitute 100 - X for Y

 

.75X + 100 - X = 80

 

-0.25X = -20

 

X = 80 = the number of 75 cent bars

 

So there are 20 one dollar bars

 

Plug these numbers back into the question to see if they work.

 

Have fun.

 

Dan