amanvermagmat wrote:
Soni and Misha are exchanging stamps with each other. At the start, Soni has 12 stamps of type X and 15 stamps of type Y while Misha has 20 stamps of type X and 10 stamps of type Y. They have no other stamps of any other type with them apart from these. After the exchange, how many stamps of type Y remain with Misha in total?
(1) During the exchange, Soni gave exactly 5 stamps of type X to Misha and received exactly 7 stamps of type Y from Misha.
(2) After the exchange, number of stamps with Soni has increased by 4.
Before ExchangeSoni = 12x and 15y ----> 27 stamps total
Misha = 20x and 10y ----> 30 stamps total
Question: After the exchange was finalized, how many Y stamps does Misha have?
(1) Immediately
not sufficient because it says
During the exchange. So we do not know what else happened before the exchange was finished.
(2) Immediately
not sufficient because there is no info about x or y stamps.
(1) + (2) During the exchange, Soni gives 5x to Misha. Misha gives 7y to Soni. Total Balance after this occured:
Soni = 7x and 22y -----> 29 total
Misha = 25x and 3y ----> 28 total.
Now statement (2) says that after the exchange was finalized, Soni has
4 more stamps. We can see that she has increased by 2 in total. Started with 27 and now has 29.
Therefore, Misha also gave an additional 2 more stamps during the exchange. But we do not know if she gave X or Y stamps.
Answer:
E