Return on Investment for apartment upgrades?

Question: How much can we spend on the individual apartments to accomplish a 25% return on investment.

Facts:
We have a recent rent survey which gives the following info on our apartments
Single rent is $925
1 bedroom, range is $1100 to $1515 and the average is $1260
2 bedroom range is $1380 to $1700 and the average is $1490.00
To be safe and because the higher rent is from superior buildings, I suggest that we aim for 87% of the high as our target after upgrade.

Presently we are getting $875 for single, $1125 for one bedroom and $1350 for 2 bedrooms.

Up grade target is granite tops, new sinks and faucets and install dishwasher and wall air and ceiling fans.
Cabinets have to be either modified or replaced to accommodate dishwasher.

The breakdown is 4 singles, 30 one bedrooms, and 6 two bedroom

So, once more, the question is how much can we spend on each apartment to accompplish a 25% return on investment for the upgrades?

Thanks!

I believe that much more info. is required do the calculation.
If I under stand correctly that you want to earn 25% return on money spent on upgrades.

What I will do is, find out how much it would cost you to do upgrade. Add 25% of it to the current return and figure out new rents to get that return.

Or in simple term whatever it cost you to renovate 1 apartment, divide 25% of that cost by 12 ( months ) and increase rent by that amount.