<PRE><B>Question 1204798</B>
&lt;br&gt;
In class A, 3/4 passed, so the ratio of pass to fail was 3:1.&lt;br&gt;
In class B, 5/8 passed, so the ratio of pass to fail was 5:3, or 5/3:1.&lt;br&gt;
Let x be the number in each class who failed.&lt;br&gt;
Then the number who passed in class A was 3x, and the number who passed in class B was (5/3)x.&lt;br&gt;
The total number of passes was 84:&lt;br&gt;
{{{3x+(5/3)x=84}}}
{{{9x+5x=252}}}
{{{14x=252}}}
{{{x=18}}}&lt;br&gt;
The total number in class A was x+3x = 18+54 = 72.
The total number in class B was x+(5/3)x = 18+30 = 48.&lt;br&gt;
ANSWER: The total number in the two classes was 72+48 = 120.&lt;br&gt;
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