There are only two ways to have 67 cents in 6 coins:

1.   1 half dollar, 3 nickels and 2 pennies
2.   2 quarters, 1 dime, 1 nickel and 2 pennies

However, since half dollars are not in circulation, there is
just one way:

2 quarters, 1 dime, 1 nickel and 2 pennies

We want 

P(nickel first AND quarter second) =

P( "1 way out of 6 or " AND "2 ways out of 5 or ) =

          × =  = 


Edwin