If the cost of corn varies directly with the number of ears purchased, and 6 ears cost 9 dollars, how many ears would cost 162 dollars

Let cost of corn = c,

no. of ears purchased = e

c varies directly as e

so

c = ke

when e = 6, c = 9

so, 9 = 6k

or k = 9/6 = 3/2.

when c = 162

c = ke

162 = 3/2 e

e = 162*2/3 = 54*2 = 108.

hence, 108 ears will cost 162$.