Question

In a Retail outlet the average revenue was Rs. 10,000 per day over a 30 day period. During this period the average daily revenue on weekends (total 8 days) was Rs. 20,000 per day. What was the average daily revenue on weekdays?

• A. 6364
• B. 5250
• C. 6570
• D. 8060

Hint:

Subtract the weekend total from the 30-day total, then divide by the number of weekdays (22).

Answer 1

The Correct Option is A

This can also be solved using the alligation (weighted deviation) method instead of plain subtraction.
The overall average revenue is $10000$ per day. The weekend average is $20000$, which is $10000$ above the overall average, and this applies to 8 days.
Let the weekday average be $x$. Its deviation below the overall average is $(10000 - x)$, and this applies to 22 days.
Since the total revenue must balance out, the weighted deviations on both sides of the overall average must be equal:\[8 \times (20000 - 10000) = 22 \times (10000 - x)\]\[8 \times 10000 = 22 \times (10000 - x)\]\[80000 = 220000 - 22x\]\[22x = 140000\]\[x = 6363.6\]Rounding gives Rs. 6364 per day as the weekday average.\[\boxed{6364}\]