Practice Consecutive numbers - quantitative aptitude Online Quiz (set-1) For All Competitive Exams

Q-1)   Average of first five odd multiples of 3 is

(a)

(b)

(c)

(d)

Explanation:

Using Rule 1,

Average of numbers = ${x_1+x_2+…+x_n}/n$

Average of first five odd multiples of 3

= ${3(1+3+5+7+9)}/5$

= ${3×25}/5$ = 15


Q-2)   The average of four consecutive even numbers is 15. The 2nd highest number is

(a)

(b)

(c)

(d)

Explanation:

x + x + 2 + x + 4 + x + 6 = 15 × 4

⇒ 4x + 12 = 60

⇒ 4x = 60 – 12 = 48

⇒ x = $48/4$ = 12

Hence, the numbers are 12, 14, 16, 18

∴ The second highest number is 16.


Q-3)   The average of nine consecutive odd numbers is 53. The least odd number is

(a)

(b)

(c)

(d)

Explanation:

x + x + 2 + x + 4 + x + 6 + x +

8 + x + 10 + x + 12 + x + 14 + x + 16 = 9 × 53

⇒ 9x + 72 = 477

⇒ 9x = 477 – 72 = 405

⇒ x = $405/9$ = 45


Q-4)   The average of four consecutive even numbers is 9. Find the largest number.

(a)

(b)

(c)

(d)

Explanation:

x + x + 2 + x + 4 + x + 6 = 9 × 4

⇒ 4x + 12 = 36

⇒ 4x = 36 – 12 = 24

∴ x = $24/4$ = 6

∴ Largest number = 6 + 6 = 12


Q-5)   If the average of 6 consecutive even numbers is 25, the difference between the largest and the smallest number is

(a)

(b)

(c)

(d)

Explanation:

Numbers = x, x + 2, ...., x + 10 Required difference

= x + 10 – x = 10


Q-6)   The average of all the odd integers between 2 and 22 is:

(a)

(b)

(c)

(d)

Explanation:

Required average

= ${3+5+7+9+11+13+15+17+19+21}/10$

= $120/10$ = 12


Q-7)   What is the average of the first six (positive) odd numbers each of which is divisible by 7?

(a)

(b)

(c)

(d)

Explanation:

Required average

= ${7+21+35+49+63+77}/6$

= ${7(1+3+5+7+9+11)}/6$

= ${7×36}/6$ = 42


Q-8)   The average of 7 consecutive numbers is 20. The largest of these numbers is :

(a)

(b)

(c)

(d)

Explanation:

Average of 7 consecutive numbers is 20.

Since the numbers are consecutive, they form an arithmetic series with common difference 1.

Since, 7 is odd, 20 must be the middle number.

We can write the series as below,

17, 18, 19, 20, 21, 22, 23

∴ The largest of these numbers is 23.


Q-9)   The average of 7 consecutive numbers is 20. The largest of these numbers is

(a)

(b)

(c)

(d)

Explanation:

Average of 7 consecutive numbers = 20

∴ Fourth number = 20

∴ Largest number = 20 + 3 = 23


Q-10)   The sum of three consecutive even numbers is 28 more than the average of these three numbers. Then the smallest of these three numbers is

(a)

(b)

(c)

(d)

Explanation:

Let three consecutive even numbers be x, x + 2 and x + 4. According to the question,

(x + x + 2 + x + 4) – ${x+x+2+x+4}/3$= 28

⇒ (3x + 6) – ${3x+6}/3$ = 28

⇒ (3x + 6) – (x + 2) = 28

⇒ 3x + 6 – x – 2 = 28

⇒ 2x + 4 = 28

⇒ 2x = 28 – 4 = 24

⇒ x = $24/2$ = 12