Given:
Weight limit on one box = 28 kilograms
Weight of each box = ⅖ kilogram
To find the greatest number of boxes of pasta she can put into one cardboard box without exceeding the weight limit, we have:

To divide the fraction, change the division sign to multiplication and flip the fraction:

Therefore, the greatest number of boxes Evelyn can put without going over the weight limit is 70 boxes.
ANSWER:
70