Answer:
Let x be the number of games Valeria played and y be the number of rides she went on. Then we can set up a system of equations:
x + y = 8 (because Valeria played 8 games and rides total)
1.5x + 3y = 21 (because each game costs $1.50 and each ride costs $3, and Valeria spent $21 in total)
We can solve for x in the first equation by subtracting y from both sides:
x = 8 - y
Then we can substitute this expression for x into the second equation:
1.5x + 3y = 21
1.5(8 - y) + 3y = 21
12 - 1.5y + 3y = 21
1.5y = 9
y = 6
So Valeria went on 6 rides. We can substitute this value for y back into the first equation and solve for x:
x + y = 8
x + 6 = 8
x = 2
So Valeria played 2 games. Therefore, Valeria played 2 games and went on 6 rides.