A boat takes 3 hours more to travel 45 km upstream than to travel 45 km downstream. If the speed of the stream is 2 km/h, what is the speed of the boat in still water?

A. 12 km/h

B. 10 km/h

C. 7 km/h

D. 8 km/h

Doubtly AI Asked 27 Oct 2026 AI-generated · not yet verified ssc cpo Save WhatsApp Report

1 answer

Best answer

Answer: D. 8 km/h

Answer: (D) 8 km/h

Let the boat's speed be b. \(\frac{45}{b - 2} - \frac{45}{b + 2} = 3\) ⇒ \(\frac{180}{b^2 - 4} = 3\) ⇒ \(b^2 = 64\), b = 8 km/h.

Check: upstream 6 km/h → 7.5 h; downstream 10 km/h → 4.5 h; difference 3 h.

Doubtly AI · 27 Oct 2026 AI-generated · not yet verified Report

Was this answer helpful?