In chad's reading class, all the students are reading the same book. the school bought each student a book at $7 per book. if there are 27 students in chad's class, which of the following expressions could not be used to calculate the total cost? a. 7(30) - 7(7) b. 7(20) + 7(7) c. 7(30) - 7(3)

It would be A. 7(30) - 7(7)

a. 7(30) - 7(7)

Step-by-step explanation:

Given,

The total number of students = 27,

∵ Every student gets a book of $ 7,

So, the total cost ( in dollars ) = price of each book × total student  

= 7 × 27

= 7(27)

∵ 7(30) - 7(7) = 7(30-7) = 7(23) ≠ 7(27)

7(20) + 7(7) = 7(20+7) = 7(27)

7(30) - 7(3) = 7(30-3) = 7(27)

Hence, option 'a' is correct.

roots are from trees

step-by-step explanation: