Question

A bag has 4 red balls and x blue balls if a ball is drawn from the bag without looking into it and the probability of getting a blue ball is 1/2,then the value of x is :
A) 2
B) 4
C) 8
D) 12

Answer 1

the answer might be 2. sorry if it is wrong

Answer 2

Option (B) - 4.

Given, No of red balls = 4

           No of blue balls = x      -------------- (1)

Total number of balls = x + 4  -------------- (2)

Given, p(blue ball) = 1/2          -------------- (3)

On solving (1),(2),(3), we get

1/2 = x/(x+4)

x+4/2 = x

x+4=2x

x = 4.


Hope this helps!