Respuesta :

n₁*$0.10 + n₂*$0.25 = $2.25

n₁ + n₂ = 12

-----------

This means that:

n₁ = 12 - n₂

And:

(12 - n₂)*$0.10 + n₂*$0.25 = $2.25

12*$0.10 - n₂*$0.10 + n₂*$0.25 = $2.25

$1.20 + n₂*$0.05*(5-2) = $2.25

$1.20 + n₂*$0.05*3 = $2.25

$1.20 + n₂*$0.15 = $2.25

n₂*$0.15 = $2.25 - $1.20

n₂*$0.15 = $1.05

n₂ = ($1.05)/($0.15)

n₂ = 7

If n₂ = 7:

n₁ + 7 = 12

Therefore, n₁ = 5.

---------

Answer:

5 dimes and 7 quarters.
The accurate answer would be 5 dimes and 7 quarters and if you add them up will equal 12 coins in total