Answer:the weekly allowance of Jeff is $16
Explanation:
Let x represent the weekly allowance of Jeff.
Jeff spent half of his weekly allowance playing mini golf. This means that the amount that Jeff spent playing golf would be
x/2. He has x/2 left.
To earn more money his parents let him wash the car for $4. This means that the total amount of money that he has left would be
x/2 + 4
If he ended up with $12, it means that
x/2 + 4 = 12
x/2 = 12 - 4 = 8
x = 8 × 2 = 16