Question: Charlie earned $10 from his job last week. He wants to buy some books costing $3 each and also save $1 for himself. Solve the equation, 1 + 3y = 10, to find y, the number of books Charlie can buy. Use algebra tiles.
A ) 2 B ) 3 C ) 5 D ) 7
Steps to derive
[Original equation.] 1 1 + 3y = 10
[Write the equation in the form of algebra tiles.]
[Subtract 1 constant tile from each side.] 3 1 + 3y - 1 = 10 - 1
[Simplify and divide both sides into three equal parts.] 4 3y = 9
