Question

Intr-un magazin sunt 15 biciclete si triciclete care au in total 38 de roti.Cate biciclete sunt?

Answer 1

b+t=15=>b=15-t
2b+3t=38
2(15-t)+3t=38
30-2t+3t=38
t=38-30
t=8 triciclete
b=15-8
b=7 biciclete