The average of 1st 3 of 4 numbers is 16 and of the last 3 are 15. If the sum of the first and the last number is 13. What is the last numbers?

A. 8
B. 6
C. 5
D. 2
A + B + C = 48
B + C + D = 45
A + D = 13
A – D = 3
A + D = 13
2D = 10
D = 5

The average age of three boys is 15 years and their ages are in proportion 3:5:7. What is the age in years of the youngest boy?

A. 15
B. 9
C. 18
D. 21
3x + 5x + 7x = 45
x =3
3x = 9

The average of first 10 odd numbers is_____________?

A. 11
B. 10
C. 12
D. 17
Sum of 10 odd no. = 100
Average = 100/10 = 10

The average of first 10 natural numbers is____________?

A. 5
B. 5.5
C. 6.5
D. 6
Sum of 10 natural no. = 110/2 = 55
Average = 55/10 = 5.5

The average of first ten prime numbers which are odd is____________?

A. 12.9
B. 13.8
C. 15.8
D. 17
Explained by: M. Zeeshan Saleem

Hi Friend !!!
Here is your answer !!!
The odd primes :-
3 , 5 , 7 , 11 , 13 , 17 , 19 , 23 , 29 , 31
Average = 3+5+7+11+13+17+19+23+29+31/10
= 158/10
= 15.8
Hope it helps u ?

The average of 11 numbers is 10.9. If the average of first six is 10.5 and that of the last six is 11.4 the sixth number is_____________?A. 11.0
B. 11.3
C. 11.4
D. 11.5

Sum of 11 numbers = 11×10.9 = 119.9
Sum of 1st 6 numbers = 6×10.5 = 63
So, sum of last 5 numbers = 119.9-63 = 56.9
And sum of last 6 numbers = 6×11.4 = 68.4
Hence sixth number will be = 68.4-56.9= 11.5

 

The average of first 10 even numbers is___________?

A. 18
B. 22
C. 9
D. 11