Question

Afla: a,b,c stiind : a+b =425 ; b=2xc ; b e cu 5 mai mic. Repede !

Answer 1

a+b=425
b=2xc => b=2c=>c=b:2
b=a-5=>a=b+5
-------------------------
a=? b=? c= ?

a+b=425
b+5+b=425
2b+5=425=>2b=425-5=>2b=420
b=210

a=b+5
a=210+5=> a=215

c=b:2
c=210:2
c=105

a+b=425       
215+210=425 

b=2c
210= 105x2
210=210

b=a-5
210=215-5
210=210

Answer 2

a+b=425
a=5+b
⇒[5+b]+b=425
⇒2b=425-5
⇒2b=420
⇒b=420/2
⇒b=210;
⇒a=5+b
⇒a=5+210
⇒a=215;
b=2c
⇒210=2c
⇒c=210/2
⇒c=105;