A) 972
B) 1012
C) 982.8
D) 812.5
Correct Answer: C
Solution :
Let the speeds off the trains A and B be x and y km/hr respectively \[\frac{Speed\text{ }of\text{ }A}{Speed\text{ }of\text{ }B}=\sqrt{\frac{\begin{align} & Time\text{ }taken\text{ }by \\ & \,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,B\text{ }after\text{ }meeting \\ \end{align}}{\begin{align} & Time\text{ }taken\text{ }by \\ & \,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,A\text{ }after\text{ }meeting \\ \end{align}}}\] \[\frac{84}{b}=\sqrt{\frac{7\frac{7}{20}}{5\frac{2}{5}}}\] \[\begin{align} & \frac{84}{b}=\frac{147}{20}\times \frac{5}{27}=\frac{7}{6} \\ & \Rightarrow \,\,\,\,b=\frac{84\times 6}{7}=72km/hr \\ \end{align}\] Total distance = \[84\times \frac{27}{5}+72\times \frac{147}{20}\] = 453.6 + 529.2 \[\Rightarrow \][982.8km]You need to login to perform this action.
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