RRB NTPC (Graduate)22 Mar 2026Shift 2Boat and Stream

A man can row at 8 km/hr in still water. When the river flows at 2 km/hr, he takes 3 hours 12 minutes to row to a destination and back. Find the distance to the destination.

एक व्यक्ति स्थिर जल में 8 km/hr की चाल से नाव चला सकता है जबकि नदी 2 km/hr की चाल से प्रवाहित हो रही हो। उसे गंतव्य तक जाने और वापस आने में 3 घंटे 12 मिनट लगते हैं। गंतव्य तक की दूरी ज्ञात कीजिए।

Answer और ExplanationAnswer and explanation

Answer: (D) 12 km

D = 8 + 2 = 10 km/h; U = 8 − 2 = 6 km/h; कुल समय = 3 h 12 min = 3.2 h
d10 + d6 = 3.2 ⇒ 8d30 = 3.2
d = 12 km
✓
दूरी 12 km है।
D = 8 + 2 = 10 km/h; U = 8 − 2 = 6 km/h; total time = 3 h 12 min = 3.2 h
d10 + d6 = 3.2 ⇒ 8d30 = 3.2
d = 12 km
✓
The distance is 12 km.
SMART APPROACH

आने-जाने की औसत चाल (Average speed) = 2 × 10 × 610 + 6 = 7.5 km/h; दूरी = 7.5 × 3.22 = 12 km।

Average speed for the round trip = 2 × 10 × 610 + 6 = 7.5 km/h; distance = 7.5 × 3.22 = 12 km.

Source: RRB NTPC (Graduate) · 22 Mar 2026 · Shift 2। Solution: Prashant Sir, Vijayastra।Source: RRB NTPC (Graduate) · 22 Mar 2026 · Shift 2. Solution by Prashant Sir, from Vijayastra.