score = (x) -> 
  if x == "Yes"
    10
  else
    0
  
weights = [0.25, 0.25, 0.25, 0.25]
water_n_sanitation = [right_to_water, preventing_risks, requiring_business_partners_to_respect_right, improving_business_partner_practices]

weights.reduce((weighted_sum, weight, index) -> 
              weighted_sum + weight*score(water_n_sanitation[index])
             , 0)