The average salary of 5 managers and 25 engineers in a company is 60000 rupees. If each of the managers received 20% salary increase while the salary of the engineers remained unchanged, the average salary of all 30 employees would have increased by 5%. The average salary, in rupees, of the engineers is

Let the average salary of managers be $$x$$ and let the average salary of engineers be $$y$$. The total salary of all the employees will be $$(5+25)*60000 = 1800000$$

We have, $$5x+25y = 1800000$$ .... (1)

If the average salary of all the employees increases by $$5\%$$, the total salary of all the employees will also increase by $$5\%$$, because the total number of employees remains the same. The new total salary will be, $$1800000\times 1.05 = 1890000$$

Also, the average salary of all the managers has increased by $$20\%$$ and has become $$1.2x$$, we have

$$5*1.2x + 25y = 1890000$$,  or  $$6x + 25y  = 1890000$$ .... (2)

Subtracting equation (1) from equation (2), we get,

$$x = 90000$$

Which gives $$25y = 1800000 - 90000*5$$  or  $$y = \dfrac{1350000}{25} = 54000$$

Therefore, the correct answer is option C.