Answer: Prakash coloured 30 pages of the book.
Explanation:
The total number of pages in the entire Harry Potter Colouring Book is 75. Aman and Prakash coloured an entire Harry Potter Colouring Book together. Aman coloured 60% of the pages. This means that the percentage of the entire Harry Potter Colouring Book that Prakash coloured would be 100 - 60 = 40%
The number of pages that Prakash coloured would be
40/100 × 75 = 0.4 × 75 = 30 pages