Let the bull be X.
x*25%=( 195-x)*2/3 1
0.25x=390/3 1-2x/3 1
x=40
Answer: Bull 40, cow 195-40= 155.
2. There are a batch of books in the bookcase, and 75% of them are returned after lending 10 books. At this time, there are 2/3 fewer books in the bookcase than before. How many books are there in the book box?
Suppose there is an X.
x( 1-75%)+ 10 = x( 1-2/3)
0.25x+ 10=x/3
x= 120
That is, there are 120 books.
Yimin soap factory plans to produce a batch of soap in 20 days. In fact, it produces 20 more boxes a day than planned, and the time required is only 80% of the original plan. How many boxes of soap were originally planned to be produced?
Suppose: X was originally planned to be produced one day.
20x=(x+20)*20*80%
x=80
That is, the original planned output: 20*80= 1600 boxes.