Alex has 7 dimes and 3 nickels. What fraction of the coins are dimes?

(# of dimes)/(total # of coins)

To find the fraction of the coins that are dimes, we need to divide the number of dimes by the total number of coins.

Alex has 7 dimes and 3 nickels, so the total number of coins is 7 + 3 = 10.

Now, we can express the number of dimes as a fraction of the total number of coins:

Fraction of dimes = Number of dimes ÷ Total number of coins
= 7 ÷ 10

So, the fraction of the coins that are dimes is 7/10.