The mean will be calculates as follows; from the formula of z-score we shall have:
z=(x-μ)/σ
the z-score associated with 0.5% is 0
thus
0=
(8-μ)/0.4=0
solving for x we get:
μ=9
Answer: μ=9
The total value is:
5. 5 x 10 ^5 * 23 x 10^3 =
= $126.5 * 10^8 =
= $1.265 x 10^10
Answer: B )
I think the orange one is correct.