Take two successive numbers, and subtract the first from the second.
I'm not 100% sure, but I think the answer is 14 hours
The line is going down (from left to right), so it has a negative slope
horizontal lines have zero slope
vertical lines have undefined slope
lines going up (from left to right) would have positive slope
This is going down so it is Choice B
All you need to remember is that the symbol ' % ' means ' /100 ',
and your life will be easy.