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3 years ago

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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 th

ere 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)

2 answers:

Molodets [167]3 years ago

8 0

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

natka813 [3]3 years ago

5 0

Answer:

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.

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Answer:

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Step-by-step explanation:

I am going to use the binomial approximation to the normal to solve this question.

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Problems of normally distributed samples can be solved using the z-score formula.

In a set with mean $\mu$ and standard deviation $\sigma$ , the zscore of a measure X is given by:

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In this problem, we have that:

$n = 276, p = 0.06$

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being the subindex 1 for the experimental group and subindex 2 for the control group.

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Step-by-step explanation:

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