Final answer:
Hakeem has 10 nickels worth $0.50, and his total coin value is at most $0.65. The number of pennies he could have ranges from 11 to 15, as he needs to have at least 21 coins and can't exceed the total value of $0.65.
Step-by-step explanation:
Hakeem has 10 nickels which are worth $0.05 each, so they would add up to $0.50. Knowing he has at least 21 coins in total and that the combined value of his coins is at most $0.65, we need to find out how many pennies he could have. A penny is worth $0.01, and since he already has $0.50 in nickels, the remaining value he can have in pennies is $0.65 - $0.50 = $0.15. Therefore, Hakeem can have up to 15 pennies.
Since he must have at least 21 coins in total and already has 10 nickels, the minimum number of pennies would be 21 - 10 = 11 pennies. So, the possible number of pennies Hakeem could have ranges from 11 to 15.