On Wednesday, Simon read ²₇ of a textbook. On Thursday, he read 30 pages of the textbook. On Friday, he read ⁵₈ of the remaining book leaving 45 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 = 8 u

Number of remaining unread pages after reading on Friday
= 8 u - 5 u
= 3 u

3 u = 45

1 u = 45 ÷ 3 = 15

Number of pages that Simon read on Friday
= 5 u
= 5 x 15
= 75

(b) 
Working backwards.

Number of pages unread after reading on Thursday
= 8 u
= 8 x 15
= 120

Total number of pages in the textbook = 7 p

Number of pages unread after reading on Wednesday 
= 7 p - 2 p
= 5 p

5 p = 30 + 120
5 p = 150

1 p = 150 ÷ 5 = 30

Total number of pages in the textbook
= 7 p
= 7 x 30
= 210

Answer(s): (a) 75; (b) 210