Aaron has 21 coins that are nickels and dimes. If his total is $1.65 how many of each type of coin does he have?

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Answer 1 · 2018-06-09T15:36:05

Refer to the explanation.

Let $x$ $x$ be the number of nickels and $y$ $y$ be the number of dimes. Then we have the simultaneous equations:

$x + y = 21$ $x+y=21$

$0.05 x + 0.1 y = 1.65$ $0.05x+0.1y=1.65$

The first equation becomes: $0.05 x + 0.05 y = 1.05$ $0.05x+0.05y=1.05$

Subtracting the second eqn. from the first, we get:

$0.05 x + 0.1 y - 0.05 x + 0.05 y = 1.65 - 1.05$ $0.05x+0.1y-0.05x+0.05y=1.65-1.05$

$0.05 y = 0.6$ $0.05y=0.6$

$y = 12$ $y=12$

$:.x+12=21$

$x=9$

So, he had $9$ nickels and $12$ dimes.