# Moderate Algebra Solved QuestionAptitude Discussion

 Q. The mean salary in ICM ltd. was Rs 1500, and the standard deviation was Rs 400. A year later each employee got a Rs 100 raise. After another year each employee's salary (including the above mentioned raise) was increased by $20%$. The standard deviation of the current salary is:
 ✖ A. 460 ✔ B. 480 ✖ C. 560 ✖ D. none of these

Solution:
Option(B) is correct

Mean salary was Rs 1500

Standard deviation = Rs 400

After 1 year all the employees got a uniform rise of Rs 100.

So, there will be no change in standard deviation.

After another year, every employee's salary was increased by $20\%$.

So, standard deviation will be increased by $20\%$.

Standard deviation

$=480\times \dfrac{120}{100}$

= Rs 480