Question

The arithmetic mean of a set of 10 numbers is 20. If each number is first multiplied by 2 and then increased by 5, then what is the mean of the new numbers?

• A. 20
• B. 25
• C. 40
• D. 45

Answer 1

Answer: (D)

45

Mean of $10$ number is $20$.
Sum of $10$ numbers = $200$
When each number is multiplied by $2$ and $5$ is added to each number, new sum = $2\times 200+10\times 5=450$
Now, new mean = $\frac{450}{10}=45$