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SECTION CA boat goes 30 km upstream and 44 km downstream in 10 hours. In 13 hours, it can go 40 kmupstream and 55 km downstream. Determine the speed of the stream and the boat in still water |
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Answer» Let the speed of the stream be = u kmphlet the speed of the boat be = v kmph speed upstream will be = v - u kmph speed downstream will be = v + u kmph 30 km upstream in time duration = 30 / (v - u) hrs44 km down stream in time duration = 44 / (v + u) hrs 44 / (v + u) + 30 / (v -u) = 10 hrs --- (1) Similarly, 40 /(v - u) + 55 / (v +u) = 13 hrs Multiply with 3/4: 30/(v-u) + 165 / 4(v+u) = 39/4 --- (2) Now (1) - (2) => [44 - 165/4] / (v+u) = 10 - 39/4 = 1/4 => v + u = 11 --- (3)Substitute this in (1) to get: 44/11 + 30/(v-u) = 10 => v - u = 30/6 = 5 --- (4) Solving (3) and (4) , we get : v = 8 kmph and u = 3 kmph Please like the solution 👍 ✔️👍 |
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