Answer
Radar reading for Auto A: $69$ $mph$
Radar reading for Auto B: $66$ $mph$
Work Step by Step
Using the cosine effect between the stationary radar gun and the moving target, the radar speed is the product of the actual speed and the cosine of the angle.
With Auto A,
Radar reading $=70mph\times\cos(10^{\circ}) = 68.94mph\approx69mph$
With Auto B,
Radar reading $=70mph\times\cos(20^{\circ}) = 65.78mph\approx66mph$
