A man has 25 25 coins in his pocket, all of which are dimes and quarters. if the total value of his change is $ 4.45 $4.45, how many dimes and how many quarters does he have?

Respuesta :

If all were dimes, the value would be $2.50. The man has $1.95 more than that amount. Trading a dime for a quarter increases the value by $0.15, so there must be
  $1.95/$0.15 = 13
quarters.

The man has 12 dimes and 13 quarters.

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Check:
  12*$0.10 +13*$0.25 = $1.20 +3.25 = $4.45 . . . (answer checks OK)