Question

a+b+c=60 ; b=a:2 ; c=a+b ;a=? ;b=? ;c=?

Answer 1

c=a+b inlocuim in suma si obtinem : 
c+c=60 , deci c= 30 , de unde a+b=30 
b=a:2 , deci a = 2b 
Inlocuim in a+b = 30 si avem : 2b+b=30 , deci b=10 si a = 2*10 = 20 

Answer 2

A=60:2=20
B=20:2=10
C=20+10=30
A+B+C=10+20+30