GMAT Prep Geometry

[moneyman]

I know I am missing something here

[aatech]

D would be the answer

From Q we know AB=OC=OB. Means triangle ABO and BCO are isoscles.

Means Angle BAD=Angle BDA = x
Means Angle DCB=Angle DBC = y

Stmt 1 - Angle COD = 60

=> Angle CDA = 120 = x + 180 - 2y => 2y-x = 60 -----(1)

Angle ABD = 180-y = 180-2x => 2x=y ------(2)

Solve 1 and 2 to get value x = 20 degree SUFF

Stmt 2 Angle BCD=40. Means Angle CBD=40

=> Angle ABD = 180-40 = 140

=> 2x+140 = 180.. Solve to get x = 20 SUFF

ANS D