HVAC&R Practice Problem of the week

[Slay the P.E.]

I used 71F for the Tdp...  I got 9.3F.   But when I substitute in 70.2F I get -3.8F  Pretty large swing. 

All answers were possible in this problem

Yep. Its badly crafted as is. The factor (3.28/.2) or (.1368/.-0083) is too big and makes the final answer too sensitive to Tdp. I need to change the relative magnitude of the given R-values to improve the problem.  

I think the problem itself is still pretty cool... just needs better numerical data. We shouldn't get a -7F to 9.3F swing by changing Tdp from 70F to 71F