Answer:
4 units count the boxes from a to b and that's 4
I = 8.
k = 4
j = sqrt(8^2 + 4^2) = 8.944.
Since they pick 3 quarts in 1 hour they can pick 6 quarts in 2 hours and 9 quarts in 3 and so on. So the number of quarts they can pick in a certain amount of hours is just the total number of hours they spend picking times 3 quarts. So since they picked for 7 hours and each of those hours they picked 3 quarts, in total they picked 21 quarts
7 x 3 = 21 quarts