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.

When three dice are thrown, write the probability of getting 4 or 5 on each of the dice simultaneously.

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.

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

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