A streaming service charges a flat monthly subscription fee of $8 plus $2 for each movie rented. In March, Lena rented 5 movies. What was her total charge for March?
For cost word problems on the SAT, immediately translate the words into a simple expression: total cost = (flat fee) + (rate per item) × (number of items). Plug in the given quantity (like number of movies), then carefully follow the order of operations: do the multiplication first, then add the flat fee. Always double-check quick arithmetic like small additions and multiplications to avoid easy mistakes.
Hints
Write an expression for the cost
Try to write the total cost as: (monthly fee) + (cost per movie) × (number of movies). What numbers go in each part?
Use the number of movies
You know Lena rented 5 movies. Substitute 5 into your expression for the number of movies.
Simplify step by step
Do the multiplication first, then add the flat fee. Be careful with each arithmetic step.
Desmos Guide
Evaluate the total cost expression
In Desmos, type 8 + 2*5 on a new line. The calculator will show the value of this expression; that value is Lena’s total charge for March.
Step-by-step Explanation
Translate the words into an expression
There is a flat monthly fee of $8 and an additional $2 for each movie.
- Let the number of movies be .
- The total charge can be written as: .
For this problem, since Lena rented 5 movies.
Substitute the number of movies
Replace with in the expression :
Now you just need to simplify .
Do the multiplication, then the addition
First multiply:
Now add this to the flat fee of $8:
So Lena’s total charge for March was $18.