Answer:
P(x=2) = 0.2368
Step-by-step explanation:
given data 
stocks of local interest N = 20 
stocks increased K = 10 
stocks decreased =  5 
remained unchanged = 5 
solution
we take here no of stock that are increased randomly n = 2 
so here Hypergeometric random variable can take integer value 
{max(0, n+k - N ), min(n,K) } = {0,2}
so here 
P(x=2) 
so 
P(x=k)  =  .......................1
      .......................1
P(x=2 ) =  
    
solve it we get 
P(x=2 ) = 0.236842
now we use excel function as
HYPGEOM.DIST (k,n,N.cumulative)   .....................2
so it will be 
HYPGEOM.DIST (2,2,10,,false) 
we get 
HYPGEOM.DIST (2,2,10,,false)  = 0.236842
so 
P(x=2) = 0.2368