The number lock of a suitcase has 4 wheels, each labelled with ten digits i.e., from 0 to 9. The lock opens with a sequence of four digits with no repeats. What is the probability of a person getting the right sequence to open the suitcase ?

A number lock on a suitcase has 3 wheels each labeled with ten digits from 0 to 9. If the opening of the lock is a particular sequence of three digits with no repeats, how many such sequences will be possible?

A bag contains 10 balls each marked with one of the digit is 0 t0 9. If 4 balls are drawn successively with replacement from the bag. What is the probability that none is marked with the digit is 0?

A bag consists of 10 balls each marked with one of the digits 0 to 9. If four balls are drawn successively with replacement from the bag, what is the probability that none is marked with the digit 0?

Numbers 1 to 10 are written on ten separate slips (one number on one slip), kept in a box and mixed well. One slip is chosen from the box without looking into it. What is the probability of : getting a 1-digit number?

If 4-digit numbers greater than 5000 are randomly formed from the digits 0, 1, 3, 5 and 7 what is the probability of forming a number divisible by 5 when, i) the digits are repeated ? ii) the repetition of digits is not allowed ?

Serial numbers for an item produced in a factory are to be made using two letters followed by four digits (0 to 9). If the letters are to be taken from the first six letters of English alphabet without repetition and the digits are also not repeated in a serial number, how many serial numbers are possible ?