Q.

An integer is chosen at random from the integers 1, 2, 3, ..., 50. The probability that the chosen integer is a multiple of at least one of 4, 6, and 7 is                    [2024]

1 825  
2 950  
3 1425  
4 2150  

Ans.

(4)

Let A, B, C be the events represents the numbers divisible by 4, 6 and 7 respectively.

   n(A)=12,  n(B)=8,  n(C)=7

       n(AB)=4,  n(BC)=1,  n(AC)=1

and n(ABC)=0

So, n(ABC)=12+8+7-4-1-1=21

   Required probability=2150