ex1
15/4= 3,75
12
---
/30
28
----
/20
20
/ /
=> 15/4 = 3,75
ex2
AB=120
AM/MB = 3/7
=> AM=3p
MB=7p => AB=10p=120 => p=12
=> AM=3•12=36
MB=7•12=84
