Question

A man can row at 8 km/hr in still water. If the
river is running at 2 km/hr, it takes him 48
minutes to row to a place and coming back. How
far is the place?​

Answer 1

Gɪᴠᴇɴ :-

• A man can row at 8 km/hr in still water.
• The river is running at 2 km/hr.
• it takes him 48 minutes to row to a place and coming back.

Tᴏ Fɪɴᴅ :-

• How far is the place ?

ᴄᴏɴᴄᴇᴘᴛ ᴜsᴇᴅ :-

• Downstream Speed = (Speed of Boat in Still water + Speed of Water in The river).

• Upstream Speed = (Speed of Boat in Still water - Speed of Water in The river).

Sᴏʟᴜᴛɪᴏɴ :-

→ Let Total Distance covered = x km.

→ Downstream Speed = (8 + 2) = 10km/h.

→ Upstream Speed = (8 - 2) = 6km/h.

→ Total Time to row to a place and coming back = 48 min. = 48/60 = 4/5 Hours.

→ Time = Distance/Speed .

A/q,

→ x/10 + x/6 = 4/5

→ (3x + 5x) /30 = 4/5

→ 8x/30 = 4/5

→ 8x * 5 = 30 * 4

→ 2x * 5 = 30

→ 10x = 30

→ x = 3 km. (Ans.)

Hence, The place is 3km Far away.