Question

in 16 biidoane de acelasi fel incep cu 5 l mai mult decat in 15 bidoane afla cati litri in 7 bidoane de acelasi fel

Answer 1

cati litri incap intr-un bidon?
16-15=1
1x5=5 l
cati litri incap in sapte bidoane de acelasi fel?
7x5 l=35 l

Answer 2

16bid=15bid+5l
⇒16bid-15bid=5l
⇒1bid=5l
⇒7bid=7·5l
⇒7bid=35l[in 7 bidoane de acelasi fel];