In a library 60% of the books are in Hindi, 60% of the remaining books are in English rest of the books are in Urdu. If there are 3600 books in English, then total no. of books in Urdu are:

Answer: Option A

Let there are X books in the library.
Number of Hindi books = 60% of X = $$\frac{60\text{X}}{100}$$  = 0.6X
Remaining Books = X - 0.6X = 0.4X
Number English books = 40% of reaming books = 60% of 0.4X = 0.24X.
Urdu Books = X-0.6X -0.24X = 0.16X
Given,
0.24X = 3600
X $$=\frac{3600}{0.24}=15000$$
Urdu Books = 0.16X = 0.16 × 15000 = 2400