The school bookstore sold 8 more pencils than pens one day. A pencil costs $0.05 and a pen costs $0.20. If the day's sales of pens and pencils totaled $8.90, how many pencils were sold?

Amount of pens sold = p

amount of pencils sold = p + 8

0.05 (p + 8) + 0.20 (p) = 8.90 each pen is $0.20 while each pencil is $0.05

0.05p + 0.4 + 0.20p = 8.90

0.25p = 8.50

amount of pens: 34

amount of pencils: 34 + 8 = 42