Question 1175437
 A child is collecting state quarters and new $1 coins.
 If she has a total of 21 coins, and the number of quarters is 9 more than the number of dollar coins, how many of each type of coin does she have?
let x = no. of dollar coins
She has 9 more quarter than dollar coins, therefore
(x+9) = no. of quarters
:
x + (x+9) = 21
2x = 21 - 9
2x = 12
x = 12/2
x = 6 dollar coins
:
I'll let you find the number of quarters, see that they add up to 21