<PRE><B>Question 885380</B>
Suppose your average, after taking 3 quizzes, is 76 (out of 100).
 What must your average be on the next 5 quizzes to increase your average to 81 out of 100
:
let a = the average of the next 5 quizzes
:
{{{(3(76)+5a)/8}}} = 81
228 + 5a = 81 * 8
5a = 648 - 228
5a = 420
a = 420/5
a = 84 av on the last 5 quizzes</PRE>