Alejandro bought $3. 50 worth of pencils and erasers at the school store. Pencils cost $0. 50 apiece, and erasers cost $0. 75 apiece. Which equation written in standard form represents the number of pencils, p, and the number of erasers, e, that Alejandro bought? 0. 75e = 3. 50 â€" 0. 50p 0. 50p 0. 75e = 3. 50 3e = 14 â€" 2p 2p 3e = 14.