Which situation represents a proportional relationship?

A. The cost of purchasing a basket of apples for $1.25 per pound plus $5.00 for the basket

B. The cost of purchasing bananas for $5.00 per box of bananas with the delivery charge of $3.00

C. The cost of purchasing limes for $ 0.65 per pound with a coupon for $1.00 off the total cost

D. The cost of purchasing avocados for $1.75 per pound plus a shipping fee of $0.16 per pound.

D

Step-by-step explanation:

A proportional relationship is defined by a linear equation whose y-intercept is zero.

Thus, we immediately reject answers A, B, and C because all involve a non-zero y-intercept.

D is the correct answer. We combine the unit cost $1.75/lb with the shipping fee $0.16/lb, obtaining a unit cost of $1.91/lb. The desired linear equation with zero y-intercept is then

C (x) = ($1.91/lb) x, where x is the number of pounds of avocados sold.