a. Two local supermarkets sell watermelons grown at McDowell's
farm. But Biggy Market sells their watermelons for $3.99 each,
regardless of size, whereas Harmless Trail Market sells their
watermelons for $0.19 per pound. For what weight will a
watermelon at Harmless Trail cost the same as any watermelon at
Biggy? If the largest watermelon grown at McDowell's farm
weighs 18 pounds, at which place should you buy your
watermelons?​