**Average Practice Set: 1**

**Formula:**

Average = (Sum of observations)/(Number of observations)

1. The difference between the average of three consecutive even numbers and the average of the next two consecutive even numbers is 5. What is the first even number?

(1) 10

(2) 12

(3) 14

(4) Cannot be determined

**Answer : Cannot be determined**

2. Find the average of the following set of numbers

148, 88, 184, 166, 96, 122

(1) 146

(2) 142

(3) 134

(4) 132

**Answer : 134**

**Explanation:**

Average = 148 + 88 + 184 + 166 + 96 + 122/6

= 804/6 = 134

3. Find the average of the following set of numbers

155, 128, 137, 140, 160, 132

(1) 148

(2) 142

(3) 146

(4) 144

**Answer : 142**

**Explanation:**

Average = 155 + 128 + 137 + 140 + 160 + 132/6

= 852/6 = 142

4. Find the average of the following set of number

132, 148, 164, 128, 120, 136

(1) 142

(2) 136

(3) 138

(4) 144

**Answer : 138**

**Explanation:**

1/6 [132 + 148 + 164 + 128 + 120 + 136]

= 1/6[828]

= 138

5. Find the average of following set of numbers.

76, 48, 84, 66, 70, 64

(1) 72

(2) 66

(3) 68

(4) 64

**Answer : 68**

**Explanation:**

= 1/6[76 + 48 + 84 + 66 + 70 + 64]

= 1/6[408] = 68

6. The average of five position numbers is 213. The average of the first two numbers is 233.5 and the average of last two numbers is 217. What is the third number?

(1) 64

(2) 56

(3) 106

(4) Cannot be determined

**Answer : 56**

**Explanation:**

Third number

= 5 * 213 – 2 * 233.5 – 2 * 217

= 1065 – 467 – 542

= 56

7. The average of five positive numbers is 308. The average of first two numbers is 482.5 and the average of last two numbers is 258.5. What is the third number?

(1) 224

(2) 58

(3) 121

(4) Cannot be determined

**Answer : 58**

**Explanation:**

Third number

= 5 * 308 – (482.5 * 2 + 258.5 * 2)

= 1540 – (965 + 517)

= 1540 – 1482 = 58

8. The average of five numbers is 49. The average of the first and the second numbers is 48 and the average of the fourth and fifth numbers is 28. What is the third number?

(1) 92

(2) 91

(3) 95

(4) 93

**Answer : 93**

**Explanation:**

Third number = 5 * 49 – 2 * 48 – 2 * 28

= 245 – 96 – 56 = 93

9. The sum of the average of three consecutive odd numbers and three consecutive even numbers is 21. If the highest even number is 16, what is the lowest odd number?

(1) 5

(2) 7

(3) 9

(4) 11

**Answer : 5**

**Explanation: **

Even number are : 12, 14 and 16

Sum of three consecutive odd numbers

= 21 * 3 – (12 + 14 + 16) = 21

The lowest odd number = 21/3 -2 = 5

10. Average of five consecutive odd numbers is 95. What is the fourth number in descending order?

(1) 91

(2) 93

(3) 99

(4) 97

**Answer : 93**

**Explanation :**

Let the five consecutive odd numbers in descending order are (x + 4), (x + 3), x, (x – 2) and (x – 4) respectively. Then, as per question

Average = 1/5[(x + 4) + (x + 2) + x + (x – 2) + (x – 4)] = 95

= 5x/5 = 95 x = 95

Fourth number in descending order = (x – 2)

= 95 – 2 = 93