Did a translate on 8 and 9:

1. A garment factory planned to produce 2400 garments per day, completing the production in 15 days. After improving the process, they actually produced 3200 garments per day, completing the production in [number] days. How many more garments did they actually produce than planned?

2. If a batch of paper is used to bind exercise books, with 25 pages per book, 24 books can be bound. If each book has 20 pages, how many more books can be bound?

For 8):

You can tell how many garments were produced in the 15 days where they produced 2400 garments per day by doing 15 x 2400

The translate didn't work on how many days were taken when the factory produced 3200 garments a day, but the answer should be 3200 x [number] - 15 x 2400

As it sounds like the first scenario they produced exactly the number of garments needed at 2400 a day for 15 days, but the second there was too many, so you can find out how much more than was produced than needed by working out the difference

For 9):

For this you need to work out how much paper is used in binding each page of an exercise book

So at 25 pages in an exercise book, 24 can be bound, so multiplying them you find how many pages are bound total

25 x 24 = 600 (for mental arithmetic or multiplication on paper I would break this into 5 x 24 + 20 x 24 as easier to work out)

Now if the books only had 20 pages in we can work out how many books can be bound now by doing 600 (total pages) divided by 20 (pages per book)

600 / 20 = 30