SOLUTION: A girl has 7 coins of different denominations. How many different sums of money can she form using 2 coins at a time?

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Question 634835: A girl has 7 coins of different denominations. How many different sums of money can she form using 2 coins at a time?
Found 2 solutions by ewatrrr, richwmiller:
Answer by ewatrrr(10682) About Me  (Show Source):
You can put this solution on YOUR website!
 

Hi

A girl has 7 coins of different denominations. 

How many different sums of money can she form using 2 coins at a time?

  7C2 = 7%21%2F%282%215%21%29+=+7%2A6%2F2+=+21 ways

Answer by richwmiller(9135) About Me  (Show Source):
You can put this solution on YOUR website!
the first coin can be any of 7 the second coin can be any of 6
7*6=42 sums assuming none can be duplicated.