There are n locks and n matching keys. Each lock gets opened by only one key which is made for it. Find the maximum number of trials required to open the locks.

There are n locks and n matching keys. If all the locks and keys are to be perfectly matched, find the maximum number of trails required to open a lock.

There are n locks and n matching keys. If all the locks and keys are to be perfectly matched, find the maximum number of trails required to open a lock.

The lock of a safe has a dial with holes, sasy ten, in which the numbers 0,1,2,……..9 are inscribed in each hole. The lock can be opened only when a specific code numbersay of six digits is dialled. Suppose the code number is 249916, it means that the can be opened when we first dial 2, then 4 nd so on. Find the maximum number of trials which do not result in opening the lock.

Find the rule which gives the number of matchsticks required to make a pattern of n such shapes.

If the maximum number of trials required to open all locks when there are n locks and n keys is 105, then n =

There are p copies each of n different subjects. Find the number of ways in which a nonempty selection can be made from them. Also find the number of ways in which at least one copy of each subject is selected.

From a set of n(n gt 1) numbers, all except one, which is n-(1)/(n) are n's . Find the mean of all the n numbers.

A number lock on a suitcase has three wheels each labelled with ten digits 0 to 9. If opening of the lock is a particular sequence of three digits with no repeats, how many such sequences will be possible? Also, find the number of unsuccessful attempts to open the lock.

There are 2 locks on the door and the door keys are among the 6 different ones you carry in your pocket . In a hurry one key is dropped somewhere by you. The probability that you can still open the door is

A nut is opened by a wrench of length 10cm. IF the least force required is 5.0N, find the moment of force needed to turn the nut.