long-term employees

[Nailya]

Of the 800 employees of Company X, 70 percent have been with the company for at least ten years. If y of these long term members were to retire and no other employee changes were to occur, what value of y would reduce the percent of long-term employees in the company to 60%?

This looks like an easy one, however, I am frustrated because my answer does not match the OA! OA is 200.
My answer 80

[scoobydooby]

70%*800=560 >10 years or Long term employees

let y out of 560 retire, so the resulting number of LT employees:
560-y and the resulting total number of employees: 800-y

(560-y)/(800-y)=60/100
=>2800-5y=2400-3y
=>2y=400
=>y=200

[Nailya]

Thank you scoobydooby!
I forgot to take into account that the total number also decreases.

[vittalgmat]

Here is another way:

70% of 800 = 560.
What if the percent of longterm employees was 60%.
ie longterm emp = 60% of 800 = 360.

So the amount of longtimers that need to retire is 560 - 360 = 200.

[Nailya]

Here is another way:

70% of 800 = 560.
What if the percent of longterm employees was 60%.
ie longterm emp = 60% of 800 = 360.

So the amount of longtimers that need to retire is 560 - 360 = 200.

but 60% of 800 is 480. that's how I tried to solve it too, but the answer was 560-480=80, not 200. we need to take into consideration that the total number decreases too.

[vittalgmat]

Here is another way:

70% of 800 = 560.
What if the percent of longterm employees was 60%.
ie longterm emp = 60% of 800 = 360.

So the amount of longtimers that need to retire is 560 - 360 = 200.

but 60% of 800 is 480. that's how I tried to solve it too, but the answer was 560-480=80, not 200. we need to take into consideration that the total number decreases too.

OOps!!! my bad. my approach is wrong..

thanks for pointing out.