Okay so to solve this, I would first multiply 21 by 4 to get 84 peaches for the 4 baskets.
To get the 1/3, the easiest way for me is to take 1/3 of 21 (# of peaches a full basket holds.) 1/3 of 21 is 7.
Then, you would add 84 and 7to get a total of 91 peaches.