Question

daca4stilouri si 3 carti costa 100lei,iar 2 stilouri si 1 carte costa 40lei, calculeaza cat costa 1stilou si 1 carte

Answer 1

4a+3b=100
2a+1b=40→4a+2b=80
(4a+3b)-(4a+2b)=100-80
→b=20. deci o carte =20lei
2a+b=40. 2a=40-b. 2a=40-20. a=20:2.
a=10. deci. un stilou =10lei
proba:
4*10+20*3=40+60=100lei