Question
A boat goes 12 km an hour in still water, but takes
thrice time as much time in going the same distance against the current. The speed of the current (in km/hour) is :Solution
Let the speed of the current be x kmph. According to the question, 12/(12 – x) = 3 ⇒ 36 – 3x = 12 ⇒ 3x = 36 – 12 ⇒ x = 24/3 = 8 km/hr
14, 17, 23, 32, ?, 59
32, 64, 8, ?, 2, 4Â
9 19 39 ? 159 319
18   29   16   31   ?   33
13, 29, 65, 129, ?, 373
47, 72, 122, ?, 297, 422
What will come in place of the question mark (?) in the following series?
24, 8, 15, ?, 12, 4
12, 18, 30, 54, ?, 198
What will come in place of the question mark (?) in the following series?
9, 22, 61, ?, 217, 334
4, 7, 12, 21, 36, ?