SSC
Quantitative Aptitude
Average
Question Bank
Average (I)
question_answer
The mean of 100 items was found to be 30. If at the time of calculation, two items were wrongly taken as 32 and 12 instead of 23 and 11, the correct mean is
A)29.4
B)29.5
C)29.8
D)29.9
Correct Answer:
D
Solution :
[d] Sum of all the items \[=(100\times 30)=3000\] Correct sum \[=(3000+23+11-32-12)=2990\] Correct mean \[=\frac{2990}{100}=29.9\]