Question
A boy can swim a certain distance downstream in 6 hours
and return in 7 hours. If the rate of stream is 3 kmph then what is the speed of boy in still water?Solution
Let the speed of the boy in still water be x kmph. Then, (x + 3) × 6 = (x – 3) × 7 => 6x + 18 = 7x - 21 => x = 39 kmph
- In the given number series, find the wrong number.
5, 10, 15, 20, 25, 31, 35 8, 17, 35, 71, 143, 287
Find the wrong number in the given number series.
9, 10, 65, 27, 217, 50- Find the wrong number, in the given number series.
1, 8, 27, 65, 125, 216 Find the wrong term in the given series below.
36, 20, 32, 72, 289, 1302.5
Find the wrong number in the given number series.
630, 180, 60, 24, 12, 8, 5Find the wrong number in given number series.
6490, 6377, 6294, 6211, 6138
1 Â Â Â Â Â Â 3 Â Â Â Â Â Â 7 Â Â Â Â Â Â Â 15 Â Â Â Â Â Â Â 33
...147Â Â 490Â Â 707Â Â Â 831Â Â Â Â 895Â Â Â 930
66, 115, 34, 155, 14, 211