Problema Solution

Jonathan, a second grader, counted the money in his piggy bank. he had only quarters and dimes. when added up his money, he had 39 coins worth a total of $7.50. how many coins of each kind did he have?

Answer provided by our tutors

1 dime = 10 cents


1 quarter = 25 cents


let


d = the number of dimes, d>0, d is integer


q = the number of quarters, q>0, q is integer


when added up his money, he had 39 coins worth a total of $7.50 = 750 cents


d + q = 39


10d + 25q = 750


by solving the above system of equations we find:


d = 15 dimes


q = 24 quarters


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Jonathan has 15 dimes and 24 quarters.