Q5 of 249 Page 31

Three numbers are chosen from 1 to 20. Find the probability that they are consecutive.

Given, no from 1 to 20

Sample space=20!

Three no consecutively=18!×3!

Now, considering three numbers as a single digit, we get 18 nos and these can be arranged in ways

Three digit numbers are formed with the digits 0, 2, 4, 6 and 8. Write the probability of forming a three digit number with the same digits.

A ordinary cube has four plane faces, one face marked 2 and another face marked 3, find the probability of getting a total of 7 in 5 throws.

6 boys and 6 girls sit in a row at random. Find the probability that all the girls sit together.

If A and B are two independent events such that P(A) = 0.3 and . Find P(B).