Let the number of textbooks be x and the number of story books be y.

Equation set x+y = 560 ...

Is yours 1/4 (one quarter) or 4/ 1 (four times)? !

Forget it. If it is a quarter system of equations, it is

x+y = 560( 1/4)x =( 1/3)y

The solution is x=320 y=240.

That is, the number of textbooks is 320 and the number of story books is 240.

If it is a quartic equation, it is

x+y=560 4x=3y

X=240 y=320。

That is, the number of textbooks is 240 and the number of story books is 320.

If you haven't learned this equation, you can just think that xy is a simple code for the number of textbooks and story books, without thinking about their meanings.