answer: $298.80
there’s 2 ways to do this:
1. First Discount: 
      40% of 830 = .40 * 830= 332
      830 - 332 = 498
   Second Discount: 
      40% of 498 = .40 * 498 = 199.20
      498 - 199.20 = 298.80
2. First Discount 
      100-40 = 60% (you’re paying 60% of the price)
      60% * 830 = .60 * 830 = 498 
    Second Discount 
      60% * 498 = .60 * 498 = 298.80
      ^you’re paying 60% of discounted price