In the venn diagram, 69 farms only grow potatoes or only sugar beet.
4/5 of these 60 farms grow only potatoes.
You got a good start !
For the box that is in the Venn
you are told 48 + x = 3 (12+x)
48 + x = 36 + 3x
12 = 2x
x = 6 for the box in the Venn
THEN add up all of the numbers in the Venn these are the farms that grow beets and /or potatoes subtract this number from 100 to find the number for the lower left corner.....the number that do NOT grow potatoes or beets.