Question

A starts 3 min after B for a place 4.5 km distant B, on reaching his destination, immediately returns and after walking a km meets A. if A can walk 1 km in 18 minutes, then what is B's speed?

• A. 5 kmph
• B. 4 kmph
• C. 6 kmph
• D. 3.5 kmph

Answer 1

The Correct Option is A

The correct option is (A): 5
Explation: Explanation:
Let B's speed be \(x\) km/hr and A's speed = \(\frac{60}{18}=\frac{10}{3}\) km/hr
Distance covered by B in 3 minutes = \(\frac{x}{20}\) km
Now, time taken by A to travel 3.5 km = Time taken by B to travel 5.5 km - 3 minutes
\(= 3.5 \times\frac{3}{10} =\frac{5.5}{x}-\frac{3}{60}\)
\(=\) 1.05 +0.05 =\(\frac{5.5}{x}\)
\(=\) \(x\)=\(\frac{5.5}{1.1}\)=5 km/hr