Question

all students in peter's class have $1.05, consisting of nickels and/ or dimes. Each student has a different combination of coins, and all possible combinations of coins are included. What is the probability that Peter is unable to give his friend Jenny change for $1.00?

Answer 1

There is zero probability that he cannot make change for a dollar. If all the coins are nickels and dimes, then he must have at least one nickel, so the rest of the coins add up to a dollar.