Final answer:
The mixed number halfway between 6.4 and 6 and 1/3 is 6 and 3/10 in its simplest form.
Step-by-step explanation:
To find the mixed number halfway between 6.4 (which is 6 and 2/5 in mixed number form) and 6 and 1/3, we first convert both numbers to improper fractions with a common denominator. In this case, the common denominator is 15. Therefore, 6 and 2/5 becomes 97/15 (because 6*15 + 2*3 = 90 + 7 = 97), and 6 and 1/3 becomes 95/15 (because 6*15 + 1*5 = 90 + 5 = 95).
To find the number halfway between these two fractions, we take the average by adding them together and dividing by 2, which gives us (97/15 + 95/15) / 2 = 192/30 / 2 = 96/30, which simplifies to 3 and 3/10 or 3.2 as a mixed number. Thus, 6 and 3/10 is the mixed number halfway between 6.4 and 6 and 1/3.