Question 1162672
X equals the number in the test group.  The total of the test scores (before the lowest tests were dropped) is 80x.
<pr>
The total of the test scores after the lowest tests were dropped is 84(x-6)...or, 84x - 504.
<pr>
If the 6 lowest scores, which average 50, were dropped, this means the total of those dropped scores is 300.  This means '84x - 504' is 300 less than '80x'.
<pr>
Therefore:
<pr>
80x = (84x - 504) + 300
<pr>
Solve for x:
<pr>
80x = 84x - 204
<pr>
-4x = -204
<pr>
x = <b>51</b>