A. 819
Add all four numbers together and then divide by 4
It is not reasonable because the decimal placing on the 4.23 is greater then the one on 413. (2 is bigger then 1). When dealign with decimals it is important to remember that if the numbers before the decimal are the same for both numbers you need to look at the first decimal as though it's the first number. so we know 4 and 4 are the same. Next we look at the .23 and .13. We know that the number 2 is bigger then 1 so it's safe to say that 4.23 is larger then 4,13.
Pretty sure it's 6.8. Times 3 2/5 by 2 and you get the answer.
