Question

0.102 roes 30 km upstream 1 47A boat goes 24 km upstream and 28 km downstream in 6 hrs. It goes 30 km and 21 km downstream in 67 hrs. Find the speed of the boat in still water and also speed of the stream 111 lm

11th - 12th Class

Maths

Solution

367

4.0 (1 ratings)

( rightarrow ) Letspeed of boot be se'rmiluy ( rightarrow ) Cet speed ot stream be ( y^{prime} ) ( k m / L gamma ) bood fired in wotrean ( (x-y) ) km / Lo boat speed in downstream ( (x+y) ) (cm/hr Acc. to question [ begin{array}{l} frac{24}{x-y}+frac{28}{x+y}=6 frac{30}{x-y}+frac{21}{x+y}=6 cdot 5 end{array} ] Let ( frac{1}{x-y} ) be ( p ) ( 4 frac{1}{x+y} ) be 2 [ begin{array}{l} therefore text { now } 24 p+28 z=6-0 30 p+212=65-0 6 times 5 text { & } 2 times 4 end{array} ] ( Rightarrow theta_{1}, 20 p+1402=30 ) ( Rightarrow-frac{120 p+842=26}{562=4} ) Speed of boat ( log _{bmod } / mathrm{L}_{mathrm{v}} mathrm{x}=10 mathrm{km} / mathrm{hr} ) speed of strem 4 kn 1 hy