Final answer:
Joseph gave 75% of his sports cards to his brother and was left with 72 cards. The percentage was calculated by converting the fraction 3/4 to a decimal and then to a percent. The remaining cards were calculated by multiplying the total number of cards (288) by 1/4.
Step-by-step explanation:
The situation described involves determining the percentage and quantity of sports cards that Joseph gave to his brother and how many he had left afterwards.
Calculating the percentage
Joseph gave three fourths (3/4) of his sports cards to his brother. To find out what percent this is, simply convert the fraction to a percentage:
3/4 = 0.75
0.75 × 100 = 75%
Calculating the remaining cards
Joseph started with 288 sports cards. Since he gave away 3/4, he has 1/4 left. We calculate the remaining cards as follows:
288 × (1/4) = 288 × 0.25 = 72