This was a very simple puzzle, perhaps a bit too simple and I therefore received only two correct responses – Pratik Poddar and Mahi Saraf – well done both!
I am taking the liberty of reproducing the answer from Mahi:
donuts bought by alice= 5
donuts bought by bob= 3
Total donuts= 8
contribution by alice =2 1/2
contribution by bob= 1/3
ratio of alice to bob= 7:1
Hence, Alice will get $0.7 and Bob will get $0.1
Hope you all enjoyed the puzzle!