Books borrowed = 3/20 times

64+( 1-3/20)x = x( 1- 1/20)

x=640

There are 640 books.

I have a deposit of X yuan in the bank.

( 1-2/5)x+ 124=940

3/5x=8 16

x= 1360

I had a deposit in the bank 1360.

3. It turns out that * * * bought X and skipping rope.

( 1-3/4)x+50=3/4x

2/4x=50

x= 100

It turns out that * * * bought a skipping rope of 100.

4. See /question/43234 109.html? si=5