We know that Store S sold 90 copies in 7 days and it sold same number of copies for 5 days.
Also we know that greatest number of copies were sold on Saturday and second greatest on Friday.
So for rest of the days of the week except Friday and Saturday, store S sold the same number of copies.
From Statement(1), 8 copies were sold on Thursday.
So the following can be inferred from the above statement:
(1) Highest sales was on Saturday
(2) Second highest was on Friday
(3) For each of the rest of 5 days of the week, 8 copies were sold.
Thus total copies sold on Friday and Saturday = 90- (5 * 8) = 50
But we are not sure whether more than 11 was sold on Friday or not.
For eg the sales might be 10 on Friday and 40 on Saturday (or) 15 on Friday and 35 on Saturday. No information given. Hence insufficient. BCE
From Statement(2), 38 copies was the maximum sold in store S. No information abt the rest of the days. Insufficient. CE
Taking both statements together,
we know that on Friday, 50 - 38 =12 books were sold.
Hence Ans is (C).
Is it correct?