Answer:
70
Step-by-step explanation
Find the diagram attached
Average = Sum of scores/sample size
Given the 7 numbers
20, 20, 20, 30, 80, 80, 80
Average = 50
5 = 20+20+20+30+80+80+80+x/8
x is the score of the 8th student
50 = 330+x/8
400 = 330+x
x = 400-330
x = 70
Hence the score of the 8th student is 70
