On Tuesday, Ahmad read ³₇ of a non-fiction book. On Wednesday, he read 35 pages of the non-fiction book. On Thursday, he read ²₅ of the remaining book leaving 15 pages unread.

1. Find the number of pages read on Thursday.
2. Find the total number of pages in the non-fiction book.

(a)
Number of remaining unread pages after reading on Wednesday = 5 u

Number of remaining unread pages after reading on Thursday
= 5 u - 2 u
= 3 u

3 u = 15

1 u = 15 ÷ 3 = 5

Number of pages that Ahmad read on Thursday
= 2 u
= 2 x 5
= 10

(b) 
Working backwards.

Number of pages unread after reading on Wednesday
= 5 u
= 5 x 5
= 25

Total number of pages in the non-fiction book = 7 p

Number of pages unread after reading on Tuesday 
= 7 p - 3 p
= 4 p

4 p = 35 + 25
4 p = 60

1 p = 60 ÷ 4 = 15

Total number of pages in the non-fiction book
= 7 p
= 7 x 15
= 105

Answer(s): (a) 10; (b) 105