500× 2/5 = 200g, 500× 3/5 = 300g.

300+40=340 (gram)

200:340= 10: 17

A: The ratio of medicine to water is 10: 17.

2.600-600× 1/4=450

4+5=9

450×5/9=250 (tree)

There are 250 apricot trees.

Hehe, that's what my teacher taught me when I was at school. . . . .