Question

Dacă a supra b este 2 pe 5, atunci a supra a +b este=?

Answer 1

a/b = 2/5 ==> b = 5a/2

a/(a+b) = a/(a+5a/2) =

= a/(2a/2 +5a/2) =

= a/7a/2 =

= 2a/7a =

= 2/7

Answer 2

$\dfrac{a}{b}$=$\dfrac{2}{5}$=k

a=2k
b=5k

$\dfrac{a}{a+b}$=$\dfrac{2k}{2k+5k}$=$\dfrac{2k}{7k}$=$\dfrac{2}{7}$