Correct Answer: 6 km
Explanation:
Let the total distance = L Then, according to the question, (2L/3)/ 4 + (1 - 2/3)L/5 = 84/60 ⇒ 2L/12 + L/15 = 84/60 ⇒ L/6 + L/15 = 84/60 ⇒ 5L + 2L = 42 ⇒ 7L = 42 ∴ L = 42/7 = 6 km