We know that, area of a circle =πr2 So, Red band area =π(0.2)2=0.04π All the other than red are in the form of a ring. So , Blue band area =π((0.3)2−(0.2)2) =π((0.3−0.2)(0.3+0.2))=0.05π Similarly, yellow band area =0.07π And white band area =0.09π ∴ Required probability=
0.04π
(0.04+0.05+0.07+0.09)π
=0.16 Alternate Method: Area of red circle =π(20)2 Radius of Archry board =
