Q21. 
There are 2 positive integers $x$ and $y$. What is the probability that $x+y$ is odd? 
A.  1/4 

B.  1/3 

C.  1/2 

D.  1/5 
Q22. 
Abhishek has 9 pairs of dark blue socks and 9 pairs of black socks. He keeps them all in the same bag. If he picks out three socks at random, then what is the probability that he will get a matching pair? 
A.  $1$ 

B.  $\dfrac{2\times ^9C_2\times ^9C_1}{{18}^C_3}$ 

C.  $\dfrac{ ^9C_3\times ^9C_1}{{18}^C_3}$ 

D.  None of these 
Q23. 
The probability that a arrow fired from a point will hit the target is 1/4. Three such arrows are fired simultaneously towards the target from that very point. What is the probability that the target will be hit? 
A.  19/64 

B.  23/64 

C.  23/67 

D.  37/64 
Q24. 
$A$ and $B$ play a game where each is asked to select a number from 1 to 5. If the two numbers match, both of them win a prize. The probability that they will not win a prize in a single trial is: 
A.  1/25 

B.  24/25 

C.  20/25 

D.  23/25 