RRB NTPC Mains or Stage 2 Model Paper 4 with solutions

Question : 34 of 120

Marks: +1, -0

A circular grass lawn of 35 metres in radius has a path 7 metres wide running around it on the outside. Find the area of path.

Solution:

(a) Radius of a circular grass lawn (withoutpath) = 35 m
∴Area

= πr^2 = π (35)^2

Radius of a circular grass lawn ( with path)

= 35 + 7 = 42

m
∴Area

= πr^2 = π(42)^2

∴ Area of path

= π(42)^2 – π(35)^2

= π(422 – 352)

= π( 42 + 35) (42 –35)

= π × 77 × 7

22 /7×77× 7= 1694m^2

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