The mean of 8 numbers is 25. A ninth number, 43, is added to them. What is the mean of the 9 numbers?
Answer & explanation
Correct answer: option 3
The correct answer is Option (3) → 27
Mean \(=\) sum of the values \(\div\) number of values, so the sum = mean × number of values. Find the old sum, add the new number and divide by the new count.
Sum of the 8 numbers \(=8\times25=200\)
Sum of the 9 numbers \(=200+43=243\)
New mean \(\displaystyle=\frac{243}{9}=27\)