How much more time will it take to finish the filling the pool?

Question

The question is:

An empty pool being filled with water at a constant rate takes 8 hours to fill to \frac{3}{5} of its capacity.How much more time will it take to finish the filling the pool? (Ans 5 hr 20min)

Now here is how I am solving it:

The entire time required to fill the pool would be $\frac{40}{3}$ hours or $13$ hours and $1$ min

So how much more time would be $(13-8)$ hours will be $5$ hours and $1$ min.Why am i getting the wrong answer. I would appreciate it if someone could tell me where I am going wrong

Answer 1

Your basic reasoning is correct; however, you made two errors in converting $40/3$ hours into hours/minutes. First, $40/3$ is not $13.1$ (as you seem to imply), it's $13.\overline3$ or $13\,{1\over3}$. Second, the decimal part of this is not minutes, it's still hours. So you have $13$ and $1/3$ hours. $1/3$ of an hour is $20$ minutes. So, $40/3$ hours is $13$ hours and $20$ minutes.

Answer 2

How did you reason: "the entire time required to fill the pool would be 40/3 hours or 13 hours and 1 min."?

Hint: 40/3 seems right.