Question
The speed of a boat in still water is 7.5 times the
speed of the stream. If the difference between the upstream and downstream speed of the boats is 40 km/hr, then find the time taken by the boat to travel 260 km in upstream.Solution
Let the speed of the stream be ‘x’ km/hr Therefore, speed of the boat in still water = 7.5x km/hr Upstream speed of the boat = 7.5x – x = 6.5x km/hr Downstream speed of the boat = x + 7.5x = 8.5x km/hr According to the question, 8.5x – 6.5x = 40 => 2x = 40 => x = 20 Therefore, upstream speed of the boat = 6.5x = 130 km/hr Required time taken = 260/130 = 2 hours
What will come in place of the question mark (?) in the following series?
130, 158, 214, 298, ?, 550
What will come in place of (?) question mark in the given number series.
22, 23, 19, 28, ?, 37
8, 12, 20, 32, 52, ?, 136
5, 23, 18, 36, 31, ?
What will come in place of the question mark (?) in the following series?
3.5, 9.5, 27.5, 81.5, 243.5, 729.5, ?
144, 288, 96, 384, 76.8, ?
257, 399, 566, ?, 983, 1237
3 2 10 ? 17 16
66, 17, 81, ?, 100, -21
110, 112, 116, 122, 130, ?
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