2. 1X2+2.9=7. 1
2. 1x2+ 1.5x2=7.2
Cut 40 pieces by the first method, 80 pieces are 2.9 m and 40 pieces are1.5 m.
Using the second method to cut 20 roots, 40 roots with 2. 1 m and 20 roots with 2.9 m were obtained.
30 pieces were cut by the third method, and 60 pieces of 2. 1.5m and 1.5m were obtained.
With 90 pieces of this * * *, you can get 2.9 m 100, 2. 1 m 100, 1.5 m 100. Of course, waste is inevitable.
I can only think of at least 90 yuan for my son's homework if I want to break my scalp, hehe. .
Welcome to clap your hands or clap bricks.