Question

Two cars A and B starting at the same time meet each other after t hours in opposite directions and reach their destination after 5 hours and 6 hours respectively after the meeting. If the speed of car A is 55 km/h, then what will be the speed of car B?

• A. $$66\sqrt{12}km/h$$
• B. $$110\sqrt{3}km/h$$
• C. $$\frac{110}{\sqrt{6}}km/h$$
• D. $$\frac{55}{6}\sqrt{30}km/h$$

Answer 1

Answer:

$$\frac{55}{6}\sqrt{30}km/h$$

Solution: Given: Two cars A and B starting at the same time meet each other after t hours in opposite directions. A & B reach their destination after 5 hours and 6 hours respectively. Concept used: Distance = Speed × Time If A & B two cars start from the P & Q respectively and after X hours they at point M. They continue their journey, A takes Y hours to reach Q and B takes Z hours to reach P. Then, X = √(Y × Z) Calculation: So, t = √(6 × 5) = √30 Then, A goes in t hours = 55√30 km According to the question, B crosses the distance that A covered in t hours in 6 hours. So, the speed of B = 55√30 ÷ 6 = (55/6)√30 kmph ∴ The speed of car B is (55/6)√30 km/hr.