Probability balls problem score calculator

score.rb

def balls_score(n, q, a)
    #n is the size for which the game is played
    #q is the number of questions asked
    #a is the number of attempts
    if q<((n/2) + 1)
        return 0
    end
    k = n/10
    if k<2
        k = 2
    end
    max = (k-1.0)*(n - k/2.0)
    max = n*(k-1.0) - k*(k-1)/2.0
    score = (max - q)/max
    ans = 100*score/(2**(a-1))
    if ans<1
        return 1
    else
        return ans
    end
end