E) 12 minutes
A normal curve has approximately 95% of graph between mean - 2sd and mean + 2sd
So 95% of the times will be between 0 and 12 minutes. 6 - 2x3 to 6 + 2x3
2.5% will take over 12 minutes
Strangely 2.5% will also take less than 0 minutes to process which shows the normal curve is not perfect in this example.
Im not sure if this really helps but I hope it does
It looks like selections A and C are identical. (Neither is equivalent to 9^x.)
If B is supposed to be 3^(2x), it is equivalent to F and D and to the given expression.
Of course, D evaluates to 9^x, so is equivalent.
Choice E evaluates to 3^(x+2), which is not equivalent to 3^(2x).
The applicable choices appear to be
... B. 3^(2x)
... D. (3*3)^x
... F. (3^x)*(3^x)
I need a picture of the figures to help with this!
