Answer
82.5
Work Step by Step
There are 25 students with an overall average score of 84. Six got a 100, Three got a 60, we need to find the average of the rest. So lets make this into an equation.
$\frac{(6*100)+(3*60)+(16*x)}{25} = 84$
So we add up the scores and we get:
$\frac{780+(16*x)}{25} = 84$
And let's multiply each side by 25:
$780 + (16*x) = 2100$
Move the 780 to the other side:
$16*x = 1320$
And finally we divide each side by 16 to get our answer:
X = 82.5
