Question

Study the given data carefully and answer the question that follows:

Country	Monthly income of citizens in ₹
	I	II	III	IV	V
A	9,500	10,500	9,800	1,000	10,200
B	500	500	500	500	4,800

Identify the average monthly income of citizens in country A.

• A. 8,200
• B. 9,000
• C. 1,000
• D. 9,020

Hint:

Add the five incomes of country A and divide by five. Estimate first, since four incomes are near ten thousand and one is very low, so the average must be a little above eight thousand.

Answer 1

The Correct Option is A

Concept:

• An average can be checked quickly by estimating first and calculating afterwards, which catches a wrong option before any arithmetic is done.
• The estimate also shows why this particular average behaves the way it does.

Step 1: Estimate before calculating.
Four incomes lie close to $10{,}000$ and one is only $1{,}000$. A rough sum is about $40{,}000$, so the average should be a little above $8{,}000$.
Option (C), $1{,}000$, is the income of one citizen and not an average, and options (B) and (D) are both far above the estimate.

Step 2: Do the exact calculation.
$9{,}500 + 10{,}500 + 9{,}800 + 1{,}000 + 10{,}200 = 41{,}000$
$$\frac{41{,}000}{5} = 8{,}200$$
This agrees with the estimate.

Step 3: Note what the figure hides.
An average income of $8{,}200$ suggests that everyone earns about that much, yet no citizen of country A actually earns $8{,}200$. One person earns only $1{,}000$ while the rest earn about ten times as much.

Step 4: Draw the lesson from the table.
Country B has a very different spread, with four citizens on $500$ and one on $4{,}800$. This is exactly why average income alone is not a reliable measure of development, since it says nothing about how the income is distributed.

Final Answer: (A) 8,200