suy ra (23+n).4=(40+n).3
suy ra 92+4n=120+3n
suy ra 4n-3n=120-92
suy ra n=28
\(\frac{23+n}{40+n}=\frac{3}{4}\)
\(\Leftrightarrow4\left(23+n\right)=3\left(40+n\right)\)
\(\Leftrightarrow92+4n=120+3n\)
\(\Rightarrow4n-3n=120-92\)
\(n=28\)
vậy n=28
nhớ kb và k nha
\(\frac{23+n}{40+n}=\frac{3}{4}\)
\(\Leftrightarrow\left(23+n\right).4=\left(40+n\right).3\)
\(23.4+4n=40.3+3n\)
\(92+4n=120+3n\)
\(4n-3n=120-92\)
\(n=28\)
Vậy n =28
\(\frac{23+n}{40+n}=\frac{3}{4}\Rightarrow\hept{\begin{cases}23+n=3k\\40+n=4k\end{cases}\left(k\inℕ^∗\right)}\)
\(\Rightarrow\left(40+n\right)-\left(23+n\right)=4k-3k\)
\(\Leftrightarrow40+n-23-n=k\)
\(\Leftrightarrow k=17\)
\(\Rightarrow\frac{23+n}{40+n}=\frac{3.17}{4.17}=\frac{51}{68}\)
\(\Rightarrow n=51-23\)
\(\Rightarrow n=28\)
