Danish read 15 pages of a book in a day. Wesley read 20 pages of the same book in a day. Danish started reading the book 3 days earlier than Wesley. How many days would Wesley need to read the book to be 20 pages ahead of Danish?
In one day, Wesley reads 20 - 15 = <<20-15=5>>5 pages more than Danish.
Wesley needs to read 20 pages / 5 pages/day = <<20/5=4>>4 days to be 20 pages ahead. Answer: \boxed{4}.
To find out how many days Wesley needs to read the book to be 20 pages ahead of Danish, we first need to determine how many pages Danish has read before Wesley starts reading.
Since Danish reads 15 pages per day and started reading 3 days earlier than Wesley, he would have read a total of 15 * 3 = 45 pages before Wesley starts reading.
Now, to calculate the number of days Wesley needs to read the book to be 20 pages ahead of Danish, we need to consider the reading speed of both Danish and Wesley.
Wesley reads 20 pages per day, and he needs to be 20 pages ahead of Danish, who has already read 45 pages. Therefore, Wesley needs to read an additional 20 + 45 = 65 pages.
If Wesley reads 20 pages per day, he would need 65 / 20 = 3.25 days to read the additional pages.
Therefore, Wesley would need approximately 3.25 days to read the book and be 20 pages ahead of Danish.