Answer:
The price of each ream of paper is $ 4.
Explanation:
Let the price of each ream of paper is x dollars,
So, the price of 5 reams of paper = 5x dollars,
After paying 1 dollar tax,
Final spending = 5x + 1
According to the question,
5x + 1 = 21
By subtraction property of equality,
5x = 21 - 1
5x = 20
By division property of equality,

x = 4
Hence, the price of each ream of paper is $ 4.