On Tuesday, Lee read ²₅ of a textbook. On Wednesday, he read 32 pages of the textbook. On Thursday, he read ³₅ of the remaining book leaving 16 pages unread.

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

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

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

2 u = 16

1 u = 16 ÷ 2 = 8

Number of pages that Lee read on Thursday
= 3 u
= 3 x 8
= 24

(b) 
Working backwards.

Number of pages unread after reading on Wednesday
= 5 u
= 5 x 8
= 40

Total number of pages in the textbook = 5 p

Number of pages unread after reading on Tuesday 
= 5 p - 2 p
= 3 p

3 p = 32 + 40
3 p = 72

1 p = 72 ÷ 3 = 24

Total number of pages in the textbook
= 5 p
= 5 x 24
= 120

Answer(s): (a) 24; (b) 120