A race track is in the shape of a ring whose inner and outer circumferences are 440 m and 506 m, respectively. What is the cost of levelling the track at Rs.6/m2? ( Take π = 22/7)
Show answer & explanation
Correct answer: D
Explanation
The correct answer is option 4 i.e Rs.29,799
Explanation:
Outer circumference = 506 m
2π r = 506
r = 253/π
Inner circumference = 440 m
2π r = 440
r = 220/π
Area = πr2
Area of the track = outer area - inner area
= π × (253/π)2 - π × (220/π)2
= 1/π (2532 - 2202)
= 1/π (64009 - 48400)
= 22(1/7) × (15609) = 4966.5 m2
The cost of leveling the track = Rs.6/m $$^2$
Total cost = 4966.5 6 = Rs.29799