A man can row 90 km downstream and return in a total of 8 hours. If the speed of the boat in still water is four times the speed of the current, then the speed of the current is? |
1 km/hr 2 km/hr 4 km/hr 6 km/hr |
6 km/hr |
Ratio of speed of boat and current = 4 : 1 ATQ, \(\frac{90}{4R + 1R}\) + \(\frac{90}{4R - 1R}\) = 8 \(\frac{18}{R}\) + \(\frac{30}{R}\) = 8 \(\frac{48}{8}\) = R R = 6 Speed of current = 1R = 1 × 6 = 6 km/hr |