Fifth grade math problem: A bookshelf has two floors, with 280 volumes in total, and the upper level has 60 volumes. How many rolls do you take from the lower floor and put them on the upper floor and
Fifth grade math problem: A bookshelf has two floors, with 280 volumes in total, and the upper level has 60 volumes. How many rolls do you take from the lower floor and put them on the upper floor and the upper and lower floors?
A bookcase has two floors, with 150 books on the lower floor and 60 books on the upper floor. How many books do you take from downstairs to upstairs? The ratio of downstairs to upstairs is 2: 3?
150-( 150+60)×2/(2+3)
= 150-2 10×2/5
= 150-84
=66 copies
I hope it helps you ~
The idea is the same.