Question

afla numerele a, b si c, stiind ca a+b=300, b+c=500, iar a+c=400.

Answer 1

$a+b=300 \\ b+c=500 \\ a+c=400 \\ a+b+b+c+a+c=300+500+400 \\ 2a+2b+2c=1200 \\ 2*(a+b+c)=1200 \\ a+b+c=\frac{1200}{2} \\ a+b+c=600 \\ a=(a+b+c)-(b+c)=600-500=100 \\ b=(a+b+c)-(a+c)=600-400=200 \\ c=(a+b+c)-(a+b)=600-300=300$