Answer & Solution
Answer: Option C
Solution:
$$\eqalign{
& {\text{Speed}} = \left( {45 \times \frac{5}{{18}}} \right)\,{\text{m/sec}} \cr
& \,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\, = \left( {\frac{{25}}{2}} \right)\,{\text{m/sec}} \cr
& {\text{Time}} = 30\,{\text{sec}} \cr
& {\text{Let}}\,{\text{the}}\,{\text{length}}\,{\text{of}}\,{\text{bridge}}\,{\text{be}}\,x\,{\text{metres}} \cr
& {\text{Then}},\,\frac{{130 + x}}{{30}} = \frac{{25}}{2} \cr
& \Rightarrow 2\left( {130 + x} \right) = 750 \cr
& \Rightarrow x = 245\,m \cr} $$
