exam question

[heavycloud]

the Q is this:
u are crossing a 5,000' high ridge in level flight. the alt reads 6,500' with a setting of 30.22 which is the setting at the nearest airport which is 1800' asl. calculate ur clearance above the ridge, given that the oat is -10.

a.1300'
b.1200'
c.1100'
d.1000'

now i calculated it was b. 1200' but the book says c. what im doing wroung??

[Sam300]

I get the same answer as you, I suspect the book may have an error. C****ne or Aerocourse?

Apparently we cannot post the name cuulhane