Question

\(\dfrac{3}{x+5}=15\%\)

Answer 1

\(\dfrac{3}{x+5}=\dfrac{3}{20}\Rightarrow3.\left(x+5\right)=3.20\Rightarrow3x+15=60\Rightarrow3x=45\Rightarrow x=15\)vậy x=15

Answer 2

Có: \(15\%=0,15=\dfrac{15}{100}=\dfrac{3}{20}\)

Mà 15% = \(\dfrac{3}{x+5}\)

=> \(\dfrac{3}{x+5}=\dfrac{3}{20}\)

=> x+5 = 20

=> x= 15

Vậy x = 15