Shawn and Rhonda bought identical boxes of stationery. Shawn used hers to write 1-sheet letters and Rhonda used hers to write 3-sheet letters. Shawn used all of the envelopes and had 50 sheets of paper left, while Rhonda used all of the paper and had 50 envelopes left. The number of sheets of paper in each box was:

- 150
- 125
- 120
- 100
- 80

Let each box contain *p* sheets of paper and *e* envelopes.

Shawn wrote *p* letters, so from Shawn we learn that *p* = *e* + 50 or *e* = *p* – 50.

Rhonda, the verbal one, wrote *p*/3 letters, so from Rhonda we learn that *p*/3 + 50 = *e*

Thus we have:

*p*/3 + 50 =

*p*– 50

*p*+ 150 = 3

*p*– 150

2

*p*= 300

*p*= 150 and

*e*= 100.

Check:

Shawn used 100 envelopes and 100 sheets of paper leaving 50 sheets of paper.

Rhonda wrote 50 letters using 150 sheets of paper and 50 envelopes, leaving 50 envelopes left over.