Answer:
8 dimes and 6 quarters
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Work Shown:
d = number of dimes
q = number of quarters
d+q = 14 since this is his coin total; equation solves to d = 14-q
10d+25q = 230 which is the total value in cents
10(14-q)+25q = 230 .... apply substitution rule
140-10q+25q = 230
15q+140 = 230
15q = 230-140
15q = 90
q = 90/15
q = 6 = number of quarters
d = 14-q
d = 14-6
d = 8 = number of dimes
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Check:
8 dimes + 6 quarters = 14 coins
8 dimes = 8*10 = 80 cents
6 quarters = 6*25 = 150 cents
8 dimes + 6 quarters = 80 cents + 150 cents = 230 cents = $2.30
The answers have been confirmed.