Question 25742
test1 = T1
test2 = T2
test3 = T3
final = F

(T1 + T2 + T3)/3 = 75
that's what the problem says
solve for (T1 + T2 + T3)
(T1 + T2 + T3) = 3 x 75 = 225
also,
((T1 + T2 + T3) + F) / 5 = 80
I used 5 because the final coubts as two tests
(225 + F) / 5 = 80
225 + F = 400
F = 175
this is what the student must score on the final to average 80.