Question

A class of 25 students took a spelling test.

Two students scored 90 each
students scored 95 on each test, ten students scored 90 on each test, three students score
80 on each test and one student scored 70.

What is the average score of the spelling test rounded to one decimal place?​

Answer 1

90.6

Explanation:

I think you have the first line incorrect. You show below that 10 students scored 90, so the first line is that 2 students scored 100, not 90. The line with the score of 90 is missing the number of students, but we can find it out. Call that number x for now.

Two students scored 100 each 2

x students scored 95 on each test x

ten students scored 90 on each test 10

three students score 80 on each test 3

and one student scored 70 + 1

x + 16

There are x + 16 students accounted for. The total number of students is 25.

x + 16 = 25

x = 9

9 students scored 95 on each test.

Now add up all the points scored by all students.

Two students scored 100 each (2 * 90) 200

9 students scored 95 on each test (9 * 95) 855

ten students scored 90 on each test (10 * 90) 900

three students score 80 on each test (3 * 80) 240

and one student scored 70 (1 * 70) + 70

Sum of all points: 2245

Now we find the average grade by dividing the sum of the points by the number of students.

average = sum/number = 2265/25 = 90.6