Question

Daniel brought a total of 39 pens and pencils and he spent a total of $91. If pencils cost two dollars each and pens cost three dollars each how many of each did he buy

Answer 1

26 pencils and 13 pens

Explanation:

First, define the variables. Lets say x represents pens and y represents pencils.

Next, make 2 equations with the information provided.

2y+3x=91

y+x=39

Then, multiply the second equation by 2 so a variable (y) can be canceled out.

2y+3x=91

2y+2x=78

Subtract the 2 equations

x=13

Next, substitute 13 in for x in the second equation.

y+x=39

y+13=39

Subtract 13 from both sides, and y=26