The probability of guessing the correct answer to a certain question is p/12. If the probability of not guessing the correct answer to the same question is 3/4, the value of p is  
 
1) 3
2) 4
3) 2
4) 1

Tickets numbered 1 to 20 are mixed up and then a ticket is drawn at random. What is the probability that the ticket drawn has a number which is a multiple of 3 or 5? 
1)  1 / 2
2)  2 / 5
3)  8/ 15
4) 9 / 20
 

There are 30 cards of the same size in a bag on which natural numbers 1 to 30 are written. One card is taken out of the bag at random. Then the probability that the number on the selected card is not divisible by 3 is    
 
1) 1 / 3
2) 3 / 4
3) 2 / 3
4) 1 / 4

A die is thrown twice. The probability of the sum being odd, is
 
1) 1 / 2
2) 1 / 3
3) 1 / 4
4) 1 / 6 

There are 50 cards maked with the numbers 1 to 50. One card is drawn at random. What is the probability that number on the card is a prime number ?

1) 3 /10
2) 1 / 5
3) 1 / 4
4) 2 /15