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?
Answers
A) 390	B) 405	C) 408	D) 415	E) None
Solution:   Let X be the number of employees.   We are given that 40% of the employees are workers. Now, 40% of X is (40/100)*X =0.4X.   Hence, the number of workers is 2X/5.   All the remaining employees are executives, so the number of executives equals,   (The number of Employees)–(The number of Workers),   = X–(2X/5)   =(3X/5)   The annual income of each worker is Rs. 390.   Hence, the total annual income of all the workers together is,   = (2X/5)*390 =156X.   Also, the annual income of each executive is Rs. 420. Hence, the total income of all the executives together is,   (3X/5)×420 (2 /5)*390= 
<gadget id="calculator">(2 /5)*390</gadget>
<output>156</output>
156X.   Also, the annual income of each executive is Rs. 420. Hence, the total income of all the executives together is,   (3X/5)×420=252X   Hence, the total income of the employees is,   = 156X +252X =408X.   The average income of all the employees together equals,   Answer: Option 408156  +252= 
<gadget id="calculator">156  +252</gadget>
<output>408</output>
408X.   The average income of all the employees together equals,   Answer: Option 408
<result>C</result>
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?