Question

the mean of the ages of 10 student's of class 7 is 14 years what was the mean age of the same group of students 2 years back ​

Answer 1

NANBA..

Since the average age of a group of 5 students is 10, hence we can conclude that the total age of the 5 students is 10×5=5010×5=50

However,after 2 new students joined the group,the average age increased by 4

So, newaverageage=10+4=14newaverageage=10+4=14

The total number of students in a group is 7 after 2 new students joined in

So now we have to find the new total age of the 7 students and then minus it with the total age of the 5 students which is 50 in order to find their average age

So, total age for 7 people is= 7×14=987×14=98

So now we know that the total age at first was 50 but then after 2 new students join in,the total age became 98

So the 2 new students age is 98−50=4898−50=48

And the average age of the 2 new students is 48÷2=2448÷2=24

Therefore the answer is 24:)...

Hope usefull..