Two cyclist start from the same places in opposite directions. One is going towards north at 30kmph and the other is going towards south 40kmph. What time will they take to be 50km apart?
Choose the correct option
A) 1.32 hr B) 0.714 hrs C) 3.231 hrs D) 0.515 hrs E) 6.214 hrs

Rationale: "to be ( 30 + 40 ) km apart , they take 1 hour to be 50 km apart , they take 1 / 70 * 50 = 0.714 hrs answer is b"
Answer: B