Eight inches of heavy, wet snow are equivalent to four inches of rain. Estimate the water content in 17 inches of heavy, wet snow.

Question

Eight inches of heavy, wet snow are equivalent to four inches of rain. Estimate the water content in 17 inches of heavy, wet snow.

Ok I get 8.4 as the answer for this problem but by calculator I get 8.5 and the answer that is right is 8.5. I'm not sure what I'm doing wrong since I do the same steps on the calculator as when I'm writing it by hand.

$$17 \cdot 4 = 68, 68/8 = 8.5 $$

When I divide by hand I get 8.4 every time 8 goes into 68 8 times with a remainder of 4.

what should I be doing to get the correct answer?

Answer 1

The remainder is $4$, but $8.5$ does not mean that the remainder when dividing by $8$ is equal to $5$.

The decimal point means that whatever number follows is the number of tenths in the answer, so $8.5=8+\frac{5}{10} = 8 + \frac12$. This is the correct answer because, when dividing $68$ by $8$, you get $8$ and a remainder of $4$, and if you divide that remainder by $8$, you get $\frac48 = \frac12$, meaning that $68 / 8 = 8 + \frac42 = 8 + \frac12 = 8.5$

Answer 2

(I'll write out the long division "European" style; I have no idea how to even remotely typeset American style )

 68 : 8 = 8.5
 64      
  40
  40
   0

Note that the remainder $4$ is not simply carried to the result as decimal digit; instead, to go one digit further, we append the next digit of $68.\color{red}0$ and divide $40$ by $8$