Question

The average of eleven numbers is 20 and the average of the first five numbers is 22, while the average
of the last five numbers is 18. What is the sixth number?​

Answer 1

Answer:

Sum of 6 numbers =60×30=180

Sum of first 4 numbers =4×25=100

Sum of last 3 numbers =3×35=105

∴ Fourth number =(100+105)−180

=205−180

=25