A square was given. Inside the square there are white tiles and black tiles. Black tiles was among the diagonal of the square and dimensions of both white as well as black tiles is 1cm x 1cm. If there are 81 black tiles in the square. Then find the no of white tiles in it.
Choose the correct option:
A) 2399
B) 1600
C) 2679
D) 1697
E) 1711

Rationale: in a square , number of squares on the diagonal is equal to the tiles on a single row . if there are even number of square on a side , then total squares on the diagonal is 2 n - 1 , otherwise 2 n . as the total tiles on the diagonal are given as 81 , then number of tiles on a side = 2 n - 1 = 81 so n = 41 . so number of white tiles = 412 − 81 = 1681 − 81412 − 81 = 1681 − 81 = 1600 answer : b
Answer: B