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| Math Central | Quandaries & Queries |
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Question from Elizabeth, a student: Here is the question asked: Sarim has $1 in coins. One-fifth of the coins are dimes, two-fifteenths are nickels, and two-thirds are pennies. Tell how many of each coin he has. I am not sure how to start this problem. |
Elizabeth,
My first thought is "I this all the coins Sarim has?"
Dimes: 1/5 = 3/15
Nickels: 2/15
Pennies: 2/3 = 10/15
3/15 + 2/15 + 10/15 = 15/15 and hence this all the coins Sarim has.
Three-fifths of the coins are dimes and the number of coins is an integer, hence the number of coins is divisible by 15. Thus the number of coins is 15 or 30 or 45 or 60 ...
What if the number of coins is 15?
Coin Number Value dimes 3/15 × 15 = 3 $0.30 nickels 2/15 × 15 = 2 $0.10 pennies 10/15 × 15 = 10 $0.10 Total $0.50
So with these fractions if the total number of coins is 15 the total value is only fifty cents. What if the number of coins is 30?
Penny
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