Question

Jacob has a mean score of 78 after his first four math tests. He wants to make a B, or an average of 80, in math. What does he need to score on the fifth test to have a mean score of 80?

A.
82

B.
88

C.
94

D.
108

I also have another one.

Which of the following is a valid conclusion from the pie chart?
A.
If 60 students read four books, then 15 students read five or more books.

B.
More than half the students read fewer than 3 books.

C.
If 60 students read four books, then 120 students read two books.

D.
Twenty-two percent of the students read four or more books.

Answer 1

Hello,

Please, see the attached files.

Thanks.

Answer 2

1) B. 88

2) C. If 60 students read four books, then 120 students read two books.

Explanation:

1) Solution

Step 1: Let "x" be the 5th test score.

Scores upto the 4th tests = 4*78 = 312

Step 2: Mean of the five tests = 80

(x + 312)/5 = 80

x + 312 = 80*5

x + 312 = 400

Step 3: Now find the value of x.

x = 400 - 312

x = 88

Therefore, Jacob scored 88 in the 5th test.

2) Solution

Step 1: 60 students read four books.

Now find the number of students.

Percentage of students read four books = 12% = 0.12

Total number of students = 60/0.12 = 500

Percentage of students reads two books = 24% = 24/100 = 0.24

Number of students read two books = 0.24*500

= 120

Hope you will understand the concept.

Thank you.