Ray wants to buy an item worth 500$ in the most cost-effective way. Let's study each of the 3 cases and see with option is the best.
In the first option, he'll buy the item at list price with a coupon for $10 off. So he'll buy it at 500-10 =$490.
In the second option, he'll buy a membership for $35 and then get the item at a 15% discount. With a 15% discount, the price of the item will be 500 - (500*0.15) = 500 - 75 = $425. And with the membership price, he'll pay a total of 425 + 35 = $460.
The third option is to buy the item online at a 10% discount and pay $4 for the shipping. At 10% discount, the price of the item will be 500 - (500*0.1) = 500 - 50 = $450. And with cost of the shipping, he'll pay a total of 450+4 = $454.
So if he chooses the first option, he'll pay $490. With the second, he'll pay $460. And finally with the third, he'll pay $454.
So the third option is the most cost-effective, buying the item at $454.
Hope this helps! :)