about selecting three (3) coins, but assume that there are 5 dimes, 4 nickels, and 2 quarters. In how many possible ways can the selection be made so that the value of the coins is at least 25 cents?

Answer 1

Adriel

Suggest you list out the possibilities for the 1st, 2nd and 3rd coins, as a dime, a nickel, or a quarter, so that the value is at least 25c.

Do it systematically

N N N total 15 c reject

N N D 20 c reject

N N Q 35 c accept

N D N

N D D

N D Q

,,,

Then write out all the rows where value >= 25

For each row find the number of ways you could get that.

For example if you have DNQ, 5 dimes, 4 nickels, 2 quarters. So you could get DNQ in 5 x 4 x 2 = 40 ways

Do this for all of your rows, and add up the numbers.

Mike