## Arithmatical - Boat’s and Streams

DIRECTIONS : Problems based on Boats and Streams.
1. A boat can travel with a speed of 13 km/hr in still water. If the speed of the stream is 4 km/hr. find the time taken by the boat to go 68 km downstream? A.  2 hours B.  3 hours C.  4 hours D.  5 hours
Solution
Speed Downstream = (13 + 4) km/hr = 17 km/hr. =(68 / 17)hrs = 4 hrs.
2. The speed of a boat in still water is 15 km/hr and the rate of current is 3 km/hr. The distance travelled downstream in 12 minutes is A.  1.2 km B.  1.8 km C.  2.4 km D.  3.6 km
Solution
Speed Downstream = (15 + 3) km/hr = 18 km/hr. =(18 x 12/60)hrs = 3.6km.

3. A boat takes 19 hours for travelling downstream from point A to point B and coming back to a point C midway between A and B. If the velocity of the stream is 4 kmph and the speed of the boat in still water is 14 kmph, what is the distance between A and B ? A.  160 km B.  180 km C.  200 km D.  220 km
Solution
Speed Downstream = (14 + 4) km/hr = 18 km/hr. =(14 - 4) km/hr = 10 km/hr.. =(x/18+ x/2 / 10) = 19 = 19x / 180 = 19 x= 180.
4. A boat running downstream covers a distance of 16 km in 2 hours while for covering the same distance upstream, it takes 4 hours. What is the speed of the boat in still water? A.  4 km/hr B.  6 km/hr C.  8 km/hr D.  Data inadequate
Solution
Rate Downstream = (16 / 2) kmph = 8 kmph =(16 / 4) kmph = 4 kmph. = 1 / 2 (8 + 4)kmph = 1/2 x 12 = 6 kmph.
5. A man can row upstream at 8 kmph and downstream at 13 kmph. The speed of the stream is A.  2.5 km/hr B.  4.2 km/hr C.  5 km/hr D.  10.5 km/hr
Solution
Speed of stream = 1 / 2 (13 - 8 )kmph = 1/2 x 5 =5 /2 = 2.5
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