\(\frac{42+y}{72}=\frac{153}{171}\)
\(\Rightarrow\left(42+y\right)\times171=76\times153\)
\(\Rightarrow\left(42+y\right)\times171=11628\)
\(\Rightarrow42+y=11628:171=68\)
\(\Rightarrow y=68-42=26\)
\(\frac{42+y}{76}=\frac{153}{171}\Rightarrow171\left(42+y\right)=153.76\Rightarrow7182+171y=11628\Rightarrow171y=4446\Rightarrow y=26\)
Vậy y = 26
\(\frac{42+y}{76}=\frac{153}{171}\)
\(\left(42+y\right).171=153.76\)
\(\left(42+y\right).171=11628\)
\(42+y=11628:171\)
\(42+y=68\)
\(y=68-42\)
\(y=26\)
\(\)
