Discussion

Question:

Amit wants to reach N₂ from S₁. It would take him 90 minutes if he goes on minor arc S₁ - E₁ on OR, and then on the chord road E₁ - N₂. What is the radius of the outer ring road in km?

Explanation:

Total distance to be travelled =

S₁–E₁ arc of the Outer Ring road + Chord E₁– N₂

Given the speeds,

Total time required to travel from S₁ to N₁ = $\frac{π r}{30 π} + \frac{\sqrt{5} r}{15 \sqrt{5}} = \frac{90}{60}$

∴ r = 15 km

∴ Radius of the Outer Ring road R = 2r = 30 km

Hence, option (c).

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