the speed at which a man can row a boat in still water is 20 kmph . if he rows downstream , where the speed of current is 4 kmph , what time will he take to cover 80 metres ?
speed of the boat downstream = 20 + 4 = 24 kmph = 24 * 5 / 18 = 6.66 m / s hence time taken to cover 70 m = 70 / 6.66 = 10.51 seconds . answer : a
divide(80, multiply(add(20, 4), const_0_2778))