Răspuns :
a+b+c=1000
b-125+625=1000
b-125=375
b=375+125
b=500 ; a=500-125=>a=375
b+c=625
500+c=625 =>c=125
a+b+c=1000
375+500+125=1000
1000=1000 (verificarea)
b-125+625=1000
b-125=375
b=375+125
b=500 ; a=500-125=>a=375
b+c=625
500+c=625 =>c=125
a+b+c=1000
375+500+125=1000
1000=1000 (verificarea)
1000+125=1125
1125-625=500(in a doua biblioteca )
500-125=385(in prima biblioteca )
625-500=125(in a treia biblioteca )
1125-625=500(in a doua biblioteca )
500-125=385(in prima biblioteca )
625-500=125(in a treia biblioteca )