Answer: 60 candies
Explanation:
Well in the sample, blue is 6/6+3+7+4+20 or 6/40, 3/20 of the total amount.
Now since there are 400 candies in a large bag, and we know that 3/20 of the 400 candies should be blue, we can multiply 400 by 3/20 to get 60 candies.