Emma received grades of 68, 74, and 86 on 3 tests. What is the lowest grade she could get on a 4th test if she needs her average to be 80 or higher?
Mathematics · High School · Thu Feb 04 2021
Answered on
Given : Average = 80
Let the score of Emma in 4th test be x
Then, Average = Sum of all observations/ number of observations
80 = (68+74+86+x)/4
Cross multiplying, we get
320 = 228 + x
Now, transposing 228 to the other side
x = 320 -228
x = 92
Therefore, Emma needs to score minimum 92 marks to maintain average of 80.