Video narration
Maatrappatta indha speed-il boat upstream-aaga sella evvalavu neram edukkum? Idhai nam Bank-exam rough-work Distance-Speed-Time table-il ovvoru line-aaga nirappip paarppom. Mudhalil moondru basic formulas ninaivil vaiththukollungal. Time = Distance / Speed. Downstream speed enbathu still-water-il boat speed plus stream speed. Upstream speed enbathu still-water-il boat speed minus stream speed. Kodukkappatta equal-time condition-ai table-il ippadi ezhuthalaam: (3K - 60) / 20 = (1.5K + 60) / 16. Irandu nerangalum equal enbadhaal cross multiplication seygiroam. Adhaavathu, 16(3K - 60) = 20(1.5K + 60). Ippodhu, 48K - 960 = 30K + 1200. Enave, 18K = 2160; K = 120. Aduththa row-il distances-ai nirappungal. 3K - 60 enbathu 360 - 60, adhanaal 300 km. 1.5K + 60 enbathu 180 + 60, adhanaal 240 km. Ingedhaan mukkiyamaana turn. Question-il direction velippadaiyaaga sollappadavillai. Standard interpretation-aaga, 20 km/h original Downstream speed endrum, 16 km/h original Upstream speed endrum eduththukkolgiroam. Appodhudhaan irandu speeds-ai thaniththaniyaaga kandupidikka mudiyum. Still-water speed = (20 + 16) / 2 = 18 km/h. Stream speed = (20 - 16) / 2 = 2 km/h. Ippodhu maatram. Boat speed one-third kuraigiradhu endraal, 18-il one-third mattum meedham alla; original-in two-thirds meedham. Aagaave pudhiya still-water speed = 18 x 2/3 = 12 km/h. Stream speed twice aagiradhu, enave 2 x 2 = 4 km/h. Pudhiya Upstream speed = 12 - 4 = 8 km/h. Required distance = 2K + 64 = 2(120) + 64 = 304 km. Table-in irudhi row: Time = 304 / 8 = 38 hours. 16 km/h Upstream speed endra assumption illaiyenil data podhaadhu. Andha standard interpretation-il, maatrappatta speed-il boat 304 km upstream sella edukkum neram 38 hours.