Regarding averages in classes 1whats the average between an

Regarding averages in classes:
1)what\'s the average between an A-, A-, and a C- 2)what\'s the average between an A, A-, and C- 3)what\'s the average between an A, A, and C-?

when calculating mabey use the lowest possible mark for that range i.e a- is a 90 and the highest range i.e for an a- it\'s a 92 so in total give me 6 answers.
thanks so much

Solution

1) Average between A- ,A- and C-

A - 10 ,A- - 9 , B - 8 , B- - 7 , C - 6 , C- - 5

so

required average = (9 +9 +5)/3 = 7.66666

2) average between an A, A-, and C-

= 1/3 (10+ 9 + 5) = 8

3) the average between an A, A, and C-

required average = ( 10 +10 + 5)/3 = 25/3 = 8.333333

this score is out of 10 .