Question

Trei robinete cu acelasi debit ,pot umple o piscina in 15 ore.In cate ore 5 robinete , de acelasi fel , vor umple piscina?

Answer 1

3r...................15h
5r...................xh
d.p.
3 pe 5=15pe x
x=(5*15) pe 3
x=75 pe 3
x=25

Answer 2

Daca 3 robinete pot umple in 15 ore ,atunci
5 robinete pot umple in  "x" ore
 Sunt valori invers proportionale
Rezulta ca : 
x= 3 × 15 : 5
x= 45 : 5
x= 9
Deci 5 robinete pot umple aceeasi piscina in 9 ore