A bag contains tickets numbered 11, 12, 13, ..., 30.

Question:

A bag contains tickets numbered 11, 12, 13, ..., 30. A ticket is taken out from the bag at random. Find the probability that the number on the drawn ticket (i)  is a multiple of 7 (ii) is greater than 15 and a multiple of 5.

Solution:

GIVEN: Tickets are marked with one of the numbers 11, 12, 13…30 are placed in a bag and mixed thoroughly. One ticket is picked at random.

TO FIND: Probability of getting

(i) multiple of 7

(ii) greater than15 and multiple of 5

Total number of cards is 

(i) Numbers that are multiple of 7 are 7, 14, 21 and 28

Total numbers that are multiple of 7 from 11 to 30 is 4

We know that PROBABILITY = 

Hence probability of getting number that is multiple of 7 from 11 to 30 is 

(ii) Numbers that are greater than 15 and multiple of 5 are 20,25,30

Total numbers that are greater than 15 and multiple of 5 from 11 to 30 is 3

We know that PROBABILITY = 

Hence probability of getting numbers that is greater than 15 and multiple of 5 from 11 to 30 

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