A pot has 2 white, 6 black, 4 grey and 8 green balls. If one ball is picked randomly from the pot, what is the probability of it being black or green?

Answer: Option B

We want black or green ball
There are 6 black and 8 green balls
Total balls = 2 + 6 + 4 + 8 = 20
So Probability $$=\frac{6}{20}+\frac{8}{20}=\frac{7}{10}$$