\(\frac{ v _1}{ v _2}=\sqrt{\frac{ T _1}{ T _2}}\)
\(=\) let initial speed is \(v\)
As speed is increased by \(3\) times so final speed become \(4 v\)
\(\Rightarrow \frac{v}{4 v}=\sqrt{\frac{223}{T}}\)
\(T=3568\,K\)
So temp. in \({ }^{\circ} C =3568-273=3295^{\circ}\,C\)