Question 357818
Let a = # students in class A, b = # students in class B.
Sum of all scores in Class A = 80a,
Sum of all scores in Class B = 90b.
By the given, {{{(80a + 90b)/(a+b) = 83}}},
so {{{80a + 90b = 83a + 83b}}}, or
{{{7b = 3a}}},
{{{b = (3a)/7}}}.
Since a number between 0 and 1 has to be multiplied to a to equal b, then a>b.
Therefore class A has more students.