A boat is navigating a river with a current speed of 2

Solution

Let the speed of the boat in still water = 'x' km/h Then, upstream and downstream speed of the boat are (x - 2) km/h and (x + 2) km/h, respectively According to the question, {56/(x - 2)} - {45/(x + y)} = (75/60) Or, (56x + 112 - 45x + 90) ÷ (x² - 4) = 1.25 Or, 11x + 202 = 1.25x² - 5 Or, 1.25x² - 11x - 207 = 0 Or, 5x² - 44x - 828 = 0 Or, 5x² - 90x + 46x - 828 = 0 Or, 5x(x - 18) + 46(x - 18) = 0 Or, (5x + 46)(x - 18) = 0 So, x = 18 (since speed cannot be negative). Therefore, upstream and downstream speed of the boat is 16 km/h and 20 km/h Total distance travelled = 16 X (90/60) + 20 X (110/60) = 24 + (110/3) = (182/3) km