here an explanation, say you have two really big pizzas that are both the same exact size, now say you cut 20 pieces out of the first on and 22 out of the second. since theres more slices on the second one the pieces will be slimmer. now if you remove 17 from both, the first pizza with 20 slices will have more left over because since 20 is less than 22 the slices from the first pizza are wider making for more pizza per slice.
They didn't make it easy. Grid lines are apparently 3 apart, but the offered coordinates are all multiples of 4. It appears the only point that is in the doubly-shaded area is ...
