1CS=1C+1C+1C=3C
or C=3Cs = 3×1 uF= 3 uF
When these two combinations are connected to same source the potential net capacitance , cP=3C=3×3=9 uF
When these two combinations are connected to same source the potential difference across each combination is same.
Ratio of energy stored,
UsUp=12CsV212CpV2
Us:Up=1:9