Question

A class of 25 students took a spelling test.

Answer 1

Answer:

90.6

Step-by-step 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