While setting a plane table at a station it was found that the error in centering was 30 cm away from the ray of length 40 m drawn from the station. If the scale of the plan is 1 cm = 2 cm, the displacement of the end of the ray in plan from the true position will be

ANS:B - 0.15 cm

I think the answer should be 0.15 meter not 0.15 centimetre for given data.
30/2 = 15 centimetres.

If the answer is right then the scale of the plan is wrong, it should be 1cm = 2meter.
So answer will be (30/200) = 0.15 centimetres. It is reduction scale,
The scale should be 1cm = 2 m,
Then (1/200)*30 =0.15 cm.
(Cross multiplication) 30 cm = 30 * 2 = 60,

60/40 * 1/100 = 0.15 cm.