Pavan travelled for 15 hours. He covered the first half of the distance at 30 kmph and remaining half of the distance at 25 kmph. Find the distance travelled by Pavan. Choose the correct choice from the following choices:
A) 408 km  B) 409 km  C) 410 km  D) 412 km  E) 419 km

Rationale: let the distance travelled be x km . total time = ( x / 2 ) / 30 + ( x / 2 ) / 25 = 15 = > x / 60 + x / 50 = 15 = > ( 5 x + 6 x ) / 300 = 15 = > x = 409 km answer : b
Answer: B