### 40% of the employees in a factory are workers. All the remaining employees are executives. The annual income of each worker is Rs. 390. The annual income of each executive is Rs. 420. What is the average annual income of all the employees in the factory together? A. 390 B. 405 C. 408 D. 415

Let X be the number of employees. We are given that 40% of the employees are workers. Now, 40% of X is $\frac{40}{100} \times X=0.4 X$ Hence, the number of workers is $\frac{2 \mathrm{X}}{5}$ All the remaining employees are executives, so the number of executives equals, (The number of Employees) − (The number of Workers) $\begin{array}{l}=X-\Large\frac{2X}{5}\\ =\Large\frac{3X}{5}\end{array}$ The annual income of each worker is Rs. 390. Hence, the total annual income of all workers together is $=\frac{2 \mathrm{X}}{5} \times 390=156 \mathrm{X}$ Also, the annual income of each executive is Rs.420. Hence, the total income {of all the executives together is, $=\frac{3 \mathrm{X}}{5} \times 420=252 \mathrm{X}$ Hence, the total income of the employees is, = 156X + 252X = 408X The average income of all the employees together equals