94.
A man can row 18 kmph in still water. It takes him trice as long to row up as
to row down the river. Find the rate of stream.
Answer:
Let man’s rate upsream be x kmph. Then, his
rate downstream = 3x kmph.
∴ Rate in still water = 1/2(3x + x)
kmph = 2x kmph.
So,
2x = 18 or x = 9.
∴ Rate upstream = 9 km/hr, Rate
downstream = 27 km/hr.
Hence,
rate of stream = 1/2(27 - 9) km/hr = 9 km/hr.
