Level 3
Carl had a total of 90 notes. The notes are $10 notes and $5 notes. After he spent 20% of the $10 notes and 60% of the $5 notes on a stereo system, he was left with 4 times as many $5 notes as $10 notes. How much did the stereo system cost?
Level 3
Charlie bought $642 worth of staplers and pens. He bought thrice as many pens as staplers. He spent $334 more on pens than on staplers. Each stapler cost $1.60 more than each pen. Find the price of a stapler.
