Solution: let the science book be X and the literature book be Y.

According to the meaning of the question: y/105+x =1/5 (1)

X/X+Y+ 105= 1/4 ⑵

From equation (1): X=5Y- 105.

From equation (2): 4X=X+Y+ 105.

Replace X=5Y- 105 with 4X=X+Y+ 105.

X=30 Y=27

A: There are 27 literary books.