Question 1012920
Average =total/n
80=total/n
83=(total+98)/(n+1)
80n=total
83n+83-98=total=83n-15
Therefore, 80n=83n-15
-3n=-15
n=5
He has taken 5 tests so far,and total score is 400 for an average of 80
with 6 tests,the total will be 498, and the average is 83.