Subject: Permutations and Combinations
Name: Sarah
Who is asking: Student Level: Secondary
Question: Arnold has a dollar coin, one dime, one quarter, one nickel, and a penny. The number of different sums of money that can be formed using three coins is...
Hi Sarah,
Since each of the coins has a different value you get a different sum for each choice of three coins. Thus the number of different sums is the number of ways of selecting 3 coins from 5 coins. This quantity, called a binomial coefficient, is sometimes denoted 
and sometimes 
and its value is
Can you write down all 10 different sums?
Cheers,Penny