a= primul balot
b=al doilea balot
a+b=135 m=>a=135m-b
1/3 a+b-15 m=90 m
(135m-b):3+b-15m=90m l amplificam cu 3
135m-b+3b-45m=270m
2b=270m-135m+45m
2b=180m
b=180m:2
b=90m
a+b=135m
a+90m=135m
a=135m-90m
a=45m
1/3 din 45m=45:3=15 m ( o treime din a)
b-15m=90m-15 m=75m
raspuns corect c)
balotul a=45 m si balotul b=90m