26) If the number of quantities in group A is 10 and in group B is 8, and their individual average is 24 and 16 respectively, find the combined average of the two groups.

20.44

18.22

16.22

18.66

Answer: A

Explanation:
The combined average of the two groups is =

27) The average of square of first 6 consecutive even numbers is:

12.20

60.66

16.45

178

Answer: B

Explanation:
Here, n=6
So, Average = 2 (6+1) (2*6+1)/3
=2*7*13/3
= 182 /3
= 60.66

28) Find the average of first 4 consecutive even numbers.

2

5

1

8

Answer: B

Explanation:
Average of first n consecutive even numbers is given by:
Average= n+1
Here, n=4
So, the average = 4+1=5

29) Find the average of first 5 consecutive even numbers starting from 2 to 10, where the last even number is 10.

1

6

2

8

Answer: B

Explanation:
The average of first n consecutive even numbers starting from 2 to X, where the last even number is X, is given by:
= (X+2)/2
Here, X=10
So, the required average = (10+2)/2
= 12/2
=6

30) Find the average of the square of first 6 consecutive even numbers starting from 2 to 12, where the last even number is 12.