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
Answer:
4 2/ 7
Step-by-step explanation:
using a = a/1, convert the expression into fraction
5/1 x 6/7 to multiply the fractions, multiply the numerators and denominators separately
5x6/1x7 = 30/7 alternative form 4 2/7, 4.285714
2 would be the answer. Replace the x with the three and multiply that with the 2 and then subtract 4.