Question

tom is buying books and notebooks for school. books cost $30 each and notebooks cost $6 each. he bought 24 items in total, and it cost $240. how many notebooks did he buy?

select one:
a. 15
b. 20
c. 4
d. 10

Explanation:

Step1: Define variables

Let $x$ = number of notebooks, $y$ = number of books.

Step2: Set up total items equation

$x + y = 24$ → $y = 24 - x$

Step3: Set up total cost equation

$6x + 30y = 240$

Step4: Substitute $y$ into cost equation

$6x + 30(24 - x) = 240$

Step5: Simplify and solve for $x$

$6x + 720 - 30x = 240$
$-24x = 240 - 720$
$-24x = -480$
$x = \frac{-480}{-24} = 20$

Answer:

B. 20