Question 1025265
p=(1*3*5*...*99)/(2*4*6*...*100) 
= ((1*3*5*...*99)(2*4*6*...*100))/((2*4*6*...*100)(2*4*6*...*100))
= {{{100!/((2^50*50!)(2^50*50!))}}}
={{{100!/(2^100*50!50!)}}}

={{{C(100,50)/2^100}}}

=0.07958923739, using an ordinary scientific calculator.

The answer is now clear.

(C(n,r) is the combination of n things taken r at a time.  In your scientific calculator it is indicated as nCr.)