three numbers are drawn from 12345678 what is the probabilit

three numbers are drawn from {1,2,3,4,5,6,7,8} what is the probability that you draw the number 518 with replacement and without replacement

Solution

The order of the number should be important.

Thus to get 5 <- 1 <- 8

With replacements, probability of picking up each number would be 1/8 always

Thus,

with replacements, probability = 1/8 * 1/8 * 1/8 = 1/8³

= 1 / 512

Without replacements,

Prob (X=5) = 1/8

then P (X=1) = 1/7

and P (X=8) = 1/6

Thus, without replacements, probability = 1/8 * 1/7 * 1/6 = 1 / 336

Hope this helps. Ask if you have any queries.