John’s piggy bank contained 7 dimes and 3 quarters. he pulled out 1 coin without looking. without replacing the first coin, john then pulled out a second coin. what is the probability that both coins were dimes? express your answer in simplest form.

ill give brainiest answer for to first person to answer.

Probability Trees - See linked image

A good visual method for this is a probability tree.

Each set of branches represents the probabilities of on coin being removed, the second set is out of 9 as the first coin is taken and not replaced.
Multiply along the lines to work out the probability of each of the combinations.

*Even though only 'Dime Dime' is needed, it is best to do all of them as this way you are able to get all marks in an exam; you can also add up all the final values as a check to see if you are right.