Question
Download Solution PDFThe average of 30 numbers is 1.2. The average of the first 20 of them is 1.1 and that of the next 9 is 1. Then the last number is:
Answer (Detailed Solution Below)
Detailed Solution
Download Solution PDFGiven:
Average of 30 numbers = 1.2
Average of first 20 numbers = 1.1
Average of next 9 numbers = 1
Formula used:
Sum = Average × Number of terms
Calculation:
Sum of 30 numbers = 1.2 × 30 = 36
Sum of first 20 numbers = 1.1 × 20 = 22
Sum of next 9 numbers = 1 × 9 = 9
Last number = Total sum - (Sum of first 20 + Sum of next 9)
⇒ Last number = 36 - (22 + 9)
⇒ Last number = 36 - 31
⇒ Last number = 5
∴ The last number is 5.
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