Saved Bookmarks
| 1. |
If the upstream speed of boat and speed of stream is in the ratio of 5 : 1 and the time taken to cover the distance of 140 kms in upstream is 2 hours more than downstream then find the speed of boat in still water ?1. 28 kmph2. 20 kmph3. 12 kmph4. 24 kmph5. 22 kmph |
|
Answer» Correct Answer - Option 4 : 24 kmph GIVEN: ⇒ Total distance = 140 kms ASSUMPTION: Let the upstream speed of Boat and speed of the stream be 5x and 1x. ⇒ Speed of boat in still water = 5x + 1x = 6x ⇒ Downstream speed = 6x + 1x = 7x CALCULATION: According to the question. When travelling downstream. ⇒ Let the time taken = T hours ⇒ 7x = 140/T ----(1) When travelling upstream. Let the time taken = (T + 2) hours ⇒ 5x = 140/ (T + 2) ----(2) From eq(1) and eq(2) ⇒ T = 5 hours ⇒ x = 4 ⇒ Speed of Boat in still water = 6x = 6 x 4 = 24 kmph |
|