A boat going upstream takes 1.5 times longer than going the same distance downstream. If the water current in the river is 8 kph, calculate the speed of the boat in still water. Date of Exam May 1998 Subject Mathematics, Surveying and Transportation Engineering Problem A boat going upstream takes 1.5 times longer than going the same distance downstream. If the water current in the river is 8 kph, calculate the speed of the boat in still water. A. 30 kph C. 40 kph B. 50 kph D. 20 kph Answer Key Click here to show or hide the answer key [ C ] Solution Click here to expand or collapse this section $t_\text{go upstream} = 1.5 \, t_\text{go downstream}$ Let x = speed of the boat in still water and d = distance $\dfrac{d}{x - 8} = 1.5 \left( \dfrac{d}{x + 8} \right)$ $x + 8 = 1.5(x - 8)$ $0.5x = 20$ $x = 40 ~ \text{kph}$ ← answer Category Algebra Motion Related Problems Boat in a River Speed of the Water Current Speed of Boat in Still Water Going Upstream Going Downstream Log in or register to post comments
