Suppose that each story book is X yuan and each literary book is Y yuan.

Then y-x=6, (calculated by 6 yuan that literary books are more expensive than story books).

300y=4 times 300x (calculated by the fact that literature books cost four times as much as story books)

So x=2 and y=8 of the solution.

So literature books cost 2400 and story books cost 600.

I hope it helps you. Thank you.