Learn to calculate the average with these sample questions

This article is in continuation to the last article on arithmetic that will aid you in your preparation for government recruitment exams. Here are some practice bits along with solutions on the Average topic.

1. If a, b, c, d, e are five consecutive odd numbers, their average is?

a) a + 4 b) abcde/2 c) 5a d) 5(a + 5)
Ans: a

Solution: a, b, c, d, e
Since they are odd consecutive numbers, they are: a, a + 2, a + 4, a + 6, a + 8
The middle number here is the average
= a + 4

2. The average of first 99 even numbers is

a) 9999 b) 2 c) 100 d) 50
Ans: c

Solution:
2 × 1 , 2 × 2, ………… 2 × 99
Average = (2 × 1 + 2 × 99)/ 2 = 100

 

3. The average of 1088 real numbers is zero. At most how many of them can be negative?

a) 1087 b) 595 c) 1000 d) 100
Ans: a
Solution: The average of 1088 real numbers is zero. Therefore, almost
1088 – 1 = 1087 of them can
be negative.

 

4. The average weight of liquid in 100 bottles is 500gm. The total weight of all the bottles is 20kg. The average weight of a bottle with liquid is?

a) 700ml b) 0.7kg c) 0.25kg d) 5 kg
Ans: b
Solution: Average weight = 20 + 50/ 100
= 0.7kg

 

5. Average of 10 positive numbers is x. If each number increases by 10%, then x…

a) May decrease
b) Remains unchanged
c) Is increased by 10%
d) May either increase or
decrease
Ans: c

Solution: Average is increased by 10%

 

7. Find the average of below series

1/1×2, 1/2×3, 1/3×4……. 1/(n-1)xn, 1/nx(n-1)
a) 1/(n3 + 2) b) 2/(n2 + 1) c) n2/(n + 1) d) 1/(n + 1)
Ans: d

Solution: Sum = 1/1
– 1/2 – 1/3……1/n – 1/n+ 1
= 1 – (1/n + 1) = n/ n + 1
Average = (n/ n + 1)/n = 1/ n + 1

To be continued…

M Venkat
Director
MVK Publications
Dilsukhnagar
7671002120