Answer:
Explanation:
If Amy started with 28 dollars and bought 7 pens, then had 20.30 dollars, we can subtract to find the price of all 7 pens.
28-20.30=7.70 dollars
now to find the amount for EACH pen, we divide by 7
7.70/7=1.1
each pen costed Amy 1 dollar and 10 cents with tax