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

Correct Option: B

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.

Here , Average of 25 consecutive odd numbers = 55
∴ Mid number i.e. 13th number = 55

Correct Option: A

Here , Average of 25 consecutive odd numbers = 55
∴ Mid number i.e. 13th number = 55
∴ 25th number = 55 + 2 × 12
25th number = 55 + 24 = 79

Given , The average monthly income of A and B = ₹ 14000
⇒ A + B = 28,000 ...(i)
The average monthly income of B and C = ₹ 15600
⇒ B + C = 31,200 ...(ii)
The average monthly income of A and C = ₹ 14400
⇒ C + A = 28,800 ...(iii)
Adding, 2(A + B + C) = 88000
⇒ A + B + C = 44000

Correct Option: A

Given , The average monthly income of A and B = ₹ 14000
⇒ A + B = 28,000 ...(i)
The average monthly income of B and C = ₹ 15600
⇒ B + C = 31,200 ...(ii)
The average monthly income of A and C = ₹ 14400
⇒ C + A = 28,800 ...(iii)
Adding, 2(A + B + C) = 88000
⇒ A + B + C = 44000
From equation (i),
28000 + C = 44000
⇒ C = 44000 – 28000 = 16000

Given , Sum of 9 numbers = 9 × 50 = 450
Sum of the first 5 numbers = 5 × 54 = 270
and Sum of the last 3 numbers = 3 × 52 = 156
∴ The sixth number = Sum of 9 numbers - Sum of the first 5 numbers - Sum of the last 3 numbers

Correct Option: C

Given , Sum of 9 numbers = 9 × 50 = 450
Sum of the first 5 numbers = 5 × 54 = 270
and Sum of the last 3 numbers = 3 × 52 = 156
∴ The sixth number = Sum of 9 numbers - Sum of the first 5 numbers - Sum of the last 3 numbers
The sixth number = 450 – 270 – 156 = 24

Let Numbers = y , y + 2, ...., y + 10
∴ Required difference = largest number - smallest number

Correct Option: B

Let Numbers = y , y + 2, ...., y + 10
∴ Required difference = largest number - smallest number
Required difference = y + 10 – y = 10