"Decimal newspaper" Su Jiao elementary school mathematics sixth grade supporting test paper Unit 3
Solution: 8 copies for the upper layer and 7 copies for the lower layer.
8X-8:(7X+8)=4∶5
(8X-8)X5=(7X+8)X4
40X-40=28X+32
40X-28X=32+40
12X=72
X=6
There are 48 books on the upper level and 42 books on the lower level.