Abox contains a nickel, a penny and a dime.

find the probability of choosing first a dime and then without replacing the dime, choosing a penny.

The box only contains 3 coins, so thats our max. Since there is only 1 of each, all of them would have a probability of 1/3.

So, the probability of choosing a dime is 1/3.

Since after you picked it out and you don't put it back in, that makes our max now 1/2.

So, the probability of choosing a penny is 1/2. :D