I would go with second option...............

3rd is wrong because changes the intended meaning i.e "will sell xxxxx at the end of the year"

frnddeep wrote:Which sentence is correct and why ?

1) Amazon will sell as many as 7 million kindles by the end of year,adding significantly to its earnings since kindle owners appear to buy more books than other shoppers .

2) Amazon will have sold as many as 7 million kindles by the end of year,adding significantly to its earnings since kindle owners appear to buy more books than other shoppers .

3)Amazon will sell as many as 7 million kindles at the end of year,adding significantly to its earnings since kindle owners appear to buy more books than other shoppers

Choice 3 is clearly incorrect - the sentence intends to talk about the sale of kindles from Amazon throughout the year on a continuous basis. "at the end of year" describes an instant and is incorrect.

It appears that present is somewhere in the middle of the year. The intended meaning of the sentence is to talk of the sale of kindles by Amazon for the entire year - i.e in the part of the year that has passed, the present and the remaining time in the present year.

Choice 1 talks about the sale of kindle ONLY in the future, i.e. in the remaining time of the year. Imagine that its december 30th. Now choice 1 doesn't make much sense does it. It would mean that Amazon will sell 7 million kindles on the 31st.

Choice 1 is thus incorrect.

Choice 2 makes most sense. It says that amazon's sale of kindle will total to a 7 million for the entire year. It uses the correct tense to show that the sale occurs continuously over the entire year.

I think all three are wrong because "by the end of (the) year" signifies the use of past perfect clause that will be modified by an -ing phrase. The first part of the sentence needs to be rewritten entirely if the author's intention is to say that an action is going to happen by the end of the year. Also, all three sentences are compairing books to other shoppers. The sentences should compare actions: "... adding significantly to its earnings since kindle owners appear to buy more books than other shoppers DO"

I didnt understand why option a) and c) are wrong. please any once can guide in details