Hi heres my solution:
According to the conditions given, we get the following equations:

70% of 800 - Y shud b equal to 60% of the total employees of the company

Now here v shud note that as Y employees r retiring, the total employees will also b reduced by Y

Hence we get the following equation:

70% of 800 - Y = 60% of (800-Y)
Solving v get Y = 80 / 0.4
Hence Y = 200....Hence Ans = A

Ur mistake was that u didn't negate Y from the RHS of the equation, in which case we get the ans as 80 (Which is wrong because of the reasons mentioned above)

Hope this helps!!!

thank you rishi235..
finally got the logic..

Not following how you got y=80/.4
Is the equation: (800-y).7=(800-y).6 or am I missing something

@dbart06

we have to take 70% of 800 then - y on LHS
and 60% (800-y) on RHS

I hope you will figure out now..right?

Still confused by method.

800(.7) - y = (800-y).6 => 560-y=480-.6y How is y = 200?

Sub 480 from 560 = 80, add y to rhs =-.5y = 80/.5 = 160

dbart06 wrote:Still confused by method.

800(.7) - y = (800-y).6 => 560-y=480-.6y How is y = 200?

Sub 480 from 560 = 80, add y to rhs =-.5y = 80/.5 = 160

uptill this step ur right " 560-y=480-.6y "

take the 480 on the left hand side and Y on the right hand side

560-480 = -0.6y+Y
80 = Y( -0.6+1)

80 = 0.4Y

Y = 80/0.4 = 200

Hope its clear now..