Railways Sample Paper RRB (Group D) Sample Test Paper-12

  • question_answer
    Points A and B are 100 km apart on a highway. One car starts from A and another from B at the same time. If the cars travel in the same direction, they meet in 5 hours. If the cars travel towards each other, they meet in 1 hour. What is the speed of the faster car?

    A)  70 km/hour      

    B)  40 km/hour

    C)  60 km/hour      

    D)  80 km/hour

    Correct Answer: C

    Solution :

    [c] Let the speed of car be x and other be y Distance covered from A in 5 hrs = 5x Distance covered from B in 5 hrs = 5y ATQ When they travel in same direction Then \[5x-\,5y=100\] \[x-\,y=20\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,...(i)\]                  ? (i) When they travel towards each other Then ATQ \[\begin{align}   & ={{r}_{2}}-\,{{r}_{1}} \\  & {{C}_{2}}-\,{{C}_{1}}=66 \\  & \therefore 2\pi {{r}_{2}}=2\pi {{r}_{1}}=66 \\  & \Rightarrow 2\pi ({{r}_{2}}-\,{{r}_{1}})=66 \\  & \Rightarrow {{r}_{2}}-\,{{r}_{1}}=\frac{66}{2\pi }=\frac{66\times 7}{2\times 22}=10.5\,\,metre \\ \end{align}\] Now, adding eqn (i), & (ii) \[2x=120\]         \[x=60\,\,km/hr\] 2x=120             x=60 km/hr

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