Question

After losing 3 baseball cards, Peter gave half of his remaining cards to Bobby. If Peter gave Bobby 9 baseball cards, how many cards did Peter start with?
Linear equation:  1 2 (x - 3) = 9

Bobby claims that Peter started with 21 cards. Which statements are true about verifying Bobby’s claim? Check all that apply.

Answer 1

If Bobby claims Peter started with 21 cards, then we'll work this into our equation.

21 - 3 (that he lost) = 18
18 / 2 (the half he gave) = 9

So this means that he did have 21 cards to begin with. Please reply to this with a list of the answers that can/could be checked!

Answer 2

The answers are A, C, and D

A.) Substitute 21 for x in the original equation.

C.) Bobby’s claim that x = 21 is correct.

D.) The result of verifying Bobby’s work is 9 = 9.