On Wednesday, Fred read ⁵₈ of a textbook. On Thursday, he read 26 pages of the textbook. On Friday, he read ³₅ of the remaining book leaving 40 pages unread.

1. Find the number of pages read on Friday.
2. Find the total number of pages in the textbook.

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

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

2 u = 40

1 u = 40 ÷ 2 = 20

Number of pages that Fred read on Friday
= 3 u
= 3 x 20
= 60

(b) 
Working backwards.

Number of pages unread after reading on Thursday
= 5 u
= 5 x 20
= 100

Total number of pages in the textbook = 8 p

Number of pages unread after reading on Wednesday 
= 8 p - 5 p
= 3 p

3 p = 26 + 100
3 p = 126

1 p = 126 ÷ 3 = 42

Total number of pages in the textbook
= 8 p
= 8 x 42
= 336

Answer(s): (a) 60; (b) 336