Question
The average age of a group of four children is 11 years.
From the group, one child, whose age was 6 years more than the average age, left. Four new children, whose average age is 5 years more than the given average age, join the group. Find the new average age.Solution
Initial sum of the ages of 4 children = 11 x 4 = 44 years Age of the child leaving: 11 + 6 = 17 years Sum of the ages after one child left = 44 – 17 = 27 years Sum of the ages of 4 new children = (11 + 5) x 4 = 64 years Total sum of the ages with new children = 27 + 64 = 91 years Number of children now = 4 - 1 + 4 = 7 New average age = 91/7 = 13 years Â
Find the wrong number in the given number series.
120, 126, 138, 162, 220, 306
217Â Â Â Â 210Â Â Â Â Â 236Â Â Â Â Â 299Â Â Â Â Â 423Â Â Â Â 640
...112, 222, 440, 872, 1717 , 3424
In each of the following giving number series, a wrong number is given. Find out the wrong number?
82, 81, 86, 110, 168, 287
- 78, 86, 71, 95, 60, 112
2100, 2140, 2186, 2240, 2300, 2372
9, 10, 12, 18, 42, 160
A-5,  A,  35,  52, 78, 115
Find the wrong number in the given number series.
233, 206, 183, 152, 125, 98
Find the wrong number in the given number series.
2, 4, 12, 48, 120, 1440