A farmer has a 420 acre farm. He planted 7/12 of it with corn, but later found that 3/14 of the crop was diseases. How many acres of healthy corn did the farmer have

192.5 acres.

Step-by-step explanation:

Total area of farm the farmer had = 420 acre.

Of these he did not plant full but only 7/12th of the total acres.

Planted area with corn = 7/12 (420) = 245 acres

Of these 245 acres, 3/14th was affected by crop and the remaining part would be healthy

crop affected by disease = 3/14 (245) = 52.5 acres

Hence healthy corns = area planted for corn-diseased part of area

=245-52.5

= 192.5 acres