Three letters are dictated to three persons and an envelope is addressed to each of them the letters are inserted into the envelopes at random so that each envelope contains exactly one letter. Find the probability that at least one letter is in its proper envelope.

A person writes letters to six friends and addresses the corresponding envelopes. In how many ways can the letters be placed in the envelopes so that all of them are in a wrong envelope

Six cards and six envelopes are numbered 1, 2, 3, 4, 5, 6 and cards are to be placed in envelopes so that each envelope contains exactly one card and no card is placed in the envelope bearing the same number and moreover cards numbered 1 is always placed in envelope numbered 2. Then the number of ways it can be done is a. 264 b. 265 c. 53 d. 67

A problem is given to three students, whose chances of solving it are : 1/4, 1/3 and 1/2 respectively. Find the probability that exactly one of them may solve it.

A problem is given to three students, whose chances of solving it are : 1/3, 1/2 and 1/5 respectively. Find the probability that exactly one of them may solve it.

A person writes a letter to four of his friends. He asks each one of them to copy the letter and mail to four different persons with instruction that they move the chain similarly. Assuming that the chain is not broken and that it costs 50 paise to mail one letter. Find the amount spent on the postage when 8th set of letter is mailed.

Dipesh writes letters to four of his friends. He asks each of them to copy the letter and mail to four different persons with the request that they continue the chain similarly. Assuming that the chain is not broken and that it costs 25 paise to mail one letter, find the total money spent on postage till the 8th set of letters is mailed.

The letters of the word ‘SOCIETY’ are placed at random in a row. What is the probability that the three vowels come together ?

A problem is given to three students, whose chances of solving it are : 1/3, 1/5 and 1/6 respectively. Find the probability than exactly one of them may solve it.

A bag contains 100 bolts and 300 nuts, 50% of each have been rusted. One item is chosen at random. Find the probability that chosen item is rusted or a bolt.

A letter is known to have come from TATANAGAR or from CALCUTTA. On the envelope, just two consecutive letter. TA are visible. What is the probability that the letter had cone from TATANAGAR?