PMHUB-G FTY RTY problem - are you up to it?

A project manager needs a certain number of identical valve housings for a power station project. He starts with 100 raw items which are made as metal castings. Out of this batch, 15 are found leaking from micro-porosities in a subsequent pressure test. 6 of these housings can be recovered by a special sealing process for raw castings. 
The 91 housings are then being machined. After this process step 10 machined castings are found leaking. 3 of these items can also be saved using another sealing process for machined castings. 
The remaining 84 housings are getting mounted to the power plant pipework. During a pressure test after this process step it is found that 12 valves are leaking. Out of these a number of 6 valves can be saved by replacing the sealing rings used. 
Finally the project manager has 78 valves which he can use. What is true? 

Options : 
FTY = 0.91, RTY = 0.84 
FTY = 0.65, RTY = 0.78 
FTY = 0.84, RTY = 0.91 
FTY = 0.78, RTY = 0.65 

(source Lehman 75 problems)

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