4 and a half to fill
30 in total minus the ones already used 30 - 18 = 12
A forth of the pages she wants to save which is about 7.5 of the total
12 - 7.5
Means she only has 4.5 pages left to use before she starts using her extra vacation pages
Required expression is x/9 - 7
The answer is 0o45.......
7x / 8 = 21
7x = 8*21
x = 24
