In the figure, the chords XY and ZW are produced to meet at T such that YT = WT, ZYW = 40o and YTW = 30o. What is YXW?

A.
50^{o} 
B.
75^{o} 
C.
35^{o} 
D.
115^{o} 
E.
30^{o}
Correct Answer: Option C
Explanation
< WYT = (frac{180 – 30}{2})
= (frac{150}{2})
= 75o(base angles of isosceles D)
YXW = 75 – 40 = 35o(Exterior angle is equal to sum of interior angles)