A) 90 km/hr, 40 km/hr
B) 40 km/hr, 30 km/hr
C) 20 km/hr, 60 km/hr
D) 50 km/hr, 12 km/hr
Correct Answer: B
Solution :
Let x km/hr be the speed of truck starting from M and y km/hr be the speed of truck starting from N. Case I: If they meet at P. Speed \[=\frac{Distance}{Time}\] For M, \[x=\frac{90+a}{9}\] or\[9x=90+a\] For N, \[y=\frac{a}{9}\] or \[9y=a\] \[\Rightarrow \] \[10+y=x\] ...(1) Case II: If they meet at P. For M, \[x=\frac{a}{9/7}\] and For N, \[y=\frac{9-a}{9/7}\] \[\Rightarrow \] \[70=x+y\] ...(2) Solving (1) and (2), we get \[y=30\text{ }km/hr\]and \[x=40\text{ }km/hr\]You need to login to perform this action.
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