Question

If alvin sold 60% of his baseball cards, gave away 30% of those that were left, and still had 40 baseball cards in his possession, how many baseball cards did alvin have to begin with?

Answer 1

The number of baseball card to begin with is 143

Explanation:

Let The number of baseball cards = x

The number of sold baseball card = 60% of x

= 0.6 x

The number of left baseball card = x - 0.6 x = 0.4 x

The number of card gave away = 30 % of left cards

= 0.3 × 0.4 x = 0.12 x

The number of card left in his possession = 40

So, 0.6 x + 0.12 x + 40 = x

Or, 40 = x - 0.6 x - 0.12 x

Or, 40 = 0.28 x

∴ x =
`(40)/(0.28)` = 142.85 ≈ 143

Hence The number of baseball card to begin with is 143 Answer