Question
The average age of a group of 6 friends is 30 years. If
the oldest friend leaves the group, the average age of the remaining group decreases by 2 years. Find the age of the friend who left.Solution
Let the age of the oldest friend (who left) be y years. Total age of 6 friends = 6 x 30 = 180 years. After the oldest friend leaves, the average age of the remaining 5 friends is 30 - 2 = 28 years. So, total age of remaining 5 friends = 5 x 28 = 140 years. Now, Age of the oldest friend = Total age of 6 friends - Total age of 5 friends = y = 180 - 140 = 40 years.
4, 11, 24, 46, 74, 109
1320, 1352, 1390, 1436, 1488, 1548
30, 42, 48, 54, 65, 81, 126
Find the wrong number in given series.
2118, 2140, 2209, 2334, 2550, 2893
Find the wrong number in the given number series.
24, 47, 76, 107, 144, 189
Find the wrong number in the given number series.
65, 91, 130, 182, 286, 429
- Find the wrong number in the given number series.
16, 25, 37, 52, 72, 97 135, 148, 109, 174, 87, 200Â
768Â Â Â 2304Â Â Â 288Â Â Â 864Â Â Â 106Â Â Â 324
- Find the wrong number in the given number series.
5, 25, 30, 90, 92, 86