A dog travelled for 2 hours. He covered the first half of the distance at 10 kmph and remaining half of the distance at 5 kmph. Find the distance travelled by the dog?
Options
A) 20 km	B) 16 km	C) 6 km	D) 3 km	E) 61 km

Rationale: let the distance travelled be x km . total time = ( x / 2 ) / 10 + ( x / 2 ) / 5 = 2 = > x / 20 + x / 10 = 2 = > ( 1 x + 2 x ) / 20 = 2 = > x = 20 km answer : a
Answer: A