Question 830508: Sally spent half of her allowance going to the movies. she washed the family car and earned $8. What is her weekly allowance if she ended with $12?
Answer by KMST(5328)   (Show Source):
You can put this solution on YOUR website! THE FIFTH GRADER WAY:
Sally ended up with $12,
but before she got those $8 for washing the family car, she must have had
$12 - $8 = $4.
If she started with he whole weekly allowance,
after spending  of it,
she would have been left with the other of her weekly allowance.
Apparently, that of her weekly allowance was $4.
Then, her weekly allowance must be twice as much, meaning
2($4) = $8.
THE ALGEBRA WAY:
 = Sally's weekly allowance in $.
$ = what Sally spent going to the movies.
$ = what Sally had after going to the movies.
$ = what Sally had after going to the movies, washing the car, and getting paid for washing the car.
The problem says that equals $12, so our equation is
Solving:
We take out as a common factor and get
We subtract  from both sides of the equal sign and get
We multiply both sides of the equal sign times 
(it is the same as dividing by ) and get
|
|
|
