Two points X and Y both on latitude 60

^{o}S have longitude147^{o}E and 153^{o}W respectively. Find to the nearest kilometer the distance between X and Y measured along the parallel of latitude(Take 2(pi)R = 4 x 10^{4}km, where R is the radius of the earth)-
**A.**

16667km -
**B.**

28850km -
**C.**

8333km -
**D.**

2233km

##### Correct Answer: Option A

##### Explanation

Length of an area = (frac{theta}{360}) x 2(pi)r

Longitude difference = 147 + 153 = 30N^{o}N

distance between xy = (frac{theta}{360}) x 2(pi)R cos60^{o}

= (frac{300}{360}) x 4 x 10^{4} x (frac{1}{2})

= 1.667 x 104km(1667 km)