I'm guessing that the marked price is what the seller WANTED to get and that the selling price is what he ACTUALLY GOT.
Under this assumption, the "marked price" of the toys is irrelevant, so the answer is A or E. Now let's work with S1.
X costs the merchant 8b and Y costs the merchant 15b.
X is sold for d and Y is sold for 2d.
We want to know if
Y Profit > X Profit, or
2d - 15b > d - 8b, or
d > 7b
As with some of the other terribly written and edited questions submitted by this user, there are
Barber of Seville implications to the wording here. ("The profit on Y" seems to imply that such a profit exists, but there may have been no profit at all, in which case the problem is stated in impossible terms.)
But since profit implies a gain, I guess we have to assume
given the prompt that d - 8b > 0 and 2d - 15b > 0. Therefore d > 8b and S1 is sufficient: d - 8b > 0 implies d > 8b -- and obviously b is positive, since it represents a price paid -- so d > 7b is true and the profit on Y is greater than the profit on X.
