Answer
39%
Work Step by Step
We need to put these two numbers in one unit, and there are 60 minutes in an hour, so we obtain that the shortest day is 611 minutes long and the longest day is 847 minutes long. The new number is higher than the original number, so we use the equation for percent increase. The equation for percent increase is the following: $(\frac{new amount - original amount}{original amount})\times100$. Thus, we plug in the numbers to find: $(\frac{847-611}{611})\times100\approx39$%
