Question
A boat takes 20 hours to cover 'n' km in still water.
While traveling downstream, it takes 15 hours to cover (n - 50) km. If the speed of the boat in still water is 5 times the speed of the stream, find the speed of the stream.Solution
ATQ, Let the speed of the stream be 'y' km/h So, speed of the boat in still water = 5 × y = '4y' km/h ATQ; (n/5y) = 20 Or, n = '100y' ...... (I) Downstream speed of the boat = 5y + y = '6y' km/h ATQ; {(n - 50) /6y} = 15 Or, n - 50 = 90y ..... (II) From equations (I) and (II): So, 100y - 50 = 90y Or, 10y = 50 So, y = 5 So, speed of the stream = 5 km/h
If 314 306 x 269 394 178 1480
Then, 1/3 x + 2x - x = ?
...2, 12, 36, 80, ?, 252
640 320 160 ? 40 20
37 59 103 191 ? 719
7 15 31 63 127 ?
...3601 3602 1803 604 154 36
...12 156 256 320 356 ?
...48 50 54 57 ? 70
1 1 8 4 27 9 81
...Direction: Which of the following will replace ‘?’ in the given question?
2, ‘?’, 46, 136, 311, 605, 1086
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