Question
In a class of 30 students, the average age each student
of the class is 21 years. 4 more students join the class such that the average age of the class decreases by 12 months. Find the average age of the 4 students who joined the class.Solution
Initial sum of ages of the students in the class = 21 × 30 = 630 years
New average age of the class = 21 - 1 = 20 years
New sum of ages of the students in the class = 20 × 34 = 680 years
Sum of ages of the new students = 680 - 630 = 50 years
Required average = 50 ÷ 4 = 12.5 years
- Find the wrong number in the given number series.
12, 20, 31, 45, 62, 84 81, 154, 124, 197, 167, 235
In each of the following giving number series, a wrong number is given. Find out the wrong number?
46 23 23 34.5 70 172.5
...- Find the wrong number in the given number series.
10, 19, 3, 28, 5, 54 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
...Find the wrong number in the given number series.
2, 3, 5, 8, 13, 22, 34Find the wrong number in the given number series.
- 71, - 7, 43, 78, 103, 119
66, 115, 34, 155, 14, 211
11, 12, 20, 58, 234, 1168
Find the wrong number in the given number series.
21, 42, 84, 116, 132, 264
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