Question

Average of 21 results is 20 the average of first 10 is 14 and that of the last 10 is 20 what is the average of 11th one?

Answer 1

Answer:

Step-by-step explanation:

An average of a group of numbers is of last addition of those numbers divided by number of those numbers

Given: the average of 21 numbers Is 20

So the sum of 21 numbers is 21x20

Which equals 420

Also Given: the average of first 10 number is 24

So the sum of first 10 number is 24x10

Which equals 240

Lastly: the average of last 10 is 14

So sum Is 140

Now sum of all number is 420

And sum of first 10 and last 10 number is 240 and 140 respectively

So 240+140+x=420

Where x is the 11th number

380+x=420

X=40.

Hope it helps you.