Answer:
B.
Step-by-step explanation:
Answer:
130
Step-by-step explanation:
A standard deviation is 15, so 2 standard deviation is 30, 2 standard deviations above 100 is 100+30=130
First we calculate how many ways you can choose four books from a set of eight.
We use the formula n! / [r! * (n-r)!]
8! / [4! * 4!]
= 8*7*6*5 / 4*3*2*1 = 70 ways
Then we have to calculate how many permutations can be made from 4 objects which equals 4*3*2*1 = 24
So, the TOTAL number of ways = 70 * 24 = 1,680
