Question 1026194: sam spent half of his allowance going to the movies. He washed the family car and earned nine dollars. What is his weekly allowance if he ended with fifteen dollars?
Answer by Theo(13342)   (Show Source):
You can put this solution on YOUR website! let x equal his allowance.
he earns 9 dollars for washing the family car.
his total intake is x + 9.
he spend half of his allowance going to the movies.
this means he spent 1/2 * x going to the movies.
he has 15 dollars left.
you get:
x + 9 - 1/2 * x = 15.
combine like terms to get 1/2 * x + 9 = 15.
subtract 9 from both sides of the equation to get 1/2 * x = 15 - 9
simplify to get 1/2 * x = 6.
multiply both sides of this equation by 2 to get x = 6 * 2.
simplify to get x = 12.
his allowance must have been 12 dollars.
he washes the family car and earns 9 dollars.
he now has 21 dollars.
he spends half of his allowance, which is 12 dollars, on the movies which means he spent 6 dollars on the movies.
he now has 21 - 6 = 15 dollars.
looks good to me.
his allowance had to be 12 dollars.
|
|
|
