Tom read a book containing 480 pages by reading the same number of pages each day. If he would have finished the book 5 days earlier by reading 16 pages a day more, how many days did Tom spend reading the book? (A) 10 (B) 12 (C) 15 (D) 16 (E) 18
Let the number of days , he finished reading the book in = x, thensukh wrote:Tom read a book containing 480 pages by reading the same number of pages each day. If he would have finished the book 5 days earlier by reading 16 pages a day more, how many days did Tom spend reading the book? (A) 10 (B) 12 (C) 15 (D) 16 (E) 18
the number of pages Tom read everyday = 480/x
If the number of pages Tom read everyday is 16 pages per day more than the number of pages Tom read everyday = (480/x)+16
and the number of days , he finished reading the book in = x-5,
Total number of pages is always the same = (Number of pages Tom read everyday)*(The number of days , he finished reading the book in )
=> x * (480/x) = (x-5)*((480/x)+16)
=> 480x = (x-5)*(480+16x)
=> x*x - 5*x - 150 = 0 (Simplifying)
=> (x-15)(x+10)=0
=> x = 15
