Answer:
16 state quarters and 7 new $1 coins.
Explanation:
A child is collecting state quarters and new $1 coins.
She has a total of 23 coins.
The number of quarters is 9 more than the number of dollar coins.
Let the number of dollar coins be x.
The number of quarters will be x + 9
x + (x + 9) = 23
2x + 9 = 23
2x = 23 - 9 = 14
2x = 14 , x = 7
So the child has 7 new dollar coins and 7 + 9 = 16 state quarters.