Rajendra is working as a delivery boy in a multinational company. The company is paying him Rs90 per delivery. In a fortnight comprising 15 consecutive working days, his average earnings per day was Rs540. If his average earnings of the first 7 days was Rs519 per day and that of the last 7 days was Rs546 per day, then what was his earning on the 8th day of the fortnight?
Show answer & explanation
Correct answer: D
Explanation
The correct answer is option 4 i.e. Rs.645.
Sum of observations = Average of observations × Number of observations
According to the given question,
Total earnings of Rajendra for 15 days = 15 × 540 = 8100
Total earnings of first 7 days = 7 × 519 = 3633
Total earnings of last 7 days = 7 × 546 = 3822
Earnings of 8th day = 8100 - (3633 + 3822)
⇒ 8100 - 7455 = 645