Question
A boat can travel 30 km downstream in 45 min. The ratio
of the speed of the boat in still water to the speed of the stream is 5: 3. How much time will the boat take to cover 25 km upstream?Solution
Speed of downstream = D/T = 30 × (60/45) = 40 km/hr The ratio of the speed of the boat in still water to the speed of the stream = 5: 3 (5x, 3x) => 8x = 40 => x = 5 Speed of upstream = 5x – 3x = 2x = 10 km/hr Distance = 25 km Time = D/S = 25/10 = 2(1/2) hr = 2 hour 30 min
- Find the wrong number in the given number series.
7, 11, 20, 45, 94, 194 - Find the wrong number in the given number series.
7, 15, 29, 49, 75, 107 14Â Â Â Â 15Â Â Â Â Â 24Â Â Â Â Â Â 50Â Â Â Â Â Â 98Â Â Â Â Â 179
...128Â Â Â 384Â Â Â 48Â Â Â 144Â Â Â 20Â Â Â 54
Find the wrong number in the given number series.
3, 7, 22, 89, 445, 2677
214, 223, 248, 297, 378, 489
8Â Â Â Â 10Â Â Â Â 36Â Â Â Â Â 216Â Â Â Â Â 2592Â Â Â Â 62208
112, 119, 133, 154, 180, 217
97, 98, 107, 132, 181, 264
- Find the wrong number in the given number series.
5, 30, 255, 860, 2105, 4130