First, we need to make sure that we have the percentages of all the possible sources of energy (check that the percentages add up to 100%).
![3+42+20+27+5+3=100](https://img.qammunity.org/2023/formulas/mathematics/college/fj8oo1k1cdq4uu7zxlpdsafgf2aegguvqy.png)
Now, we can calculate the probabilities.
a)
![\begin{gathered} P(NotHydropower)=1-P(Hydropower)=1-3\text{percent}=1-0.03=0.97 \\ \Rightarrow P(NotHydropower)=0.97 \end{gathered}](https://img.qammunity.org/2023/formulas/mathematics/college/7c7ph1cjxinu7zcac1fs97kc578btpqdgz.png)
P(Not Hydropower)=0.97
b)
![\begin{gathered} P(OilOrHydropower)=P(Oil)+P(Hydropower)=0.42+0.03=0.45 \\ \Rightarrow P(OilOrHydropower)=0.45 \end{gathered}](https://img.qammunity.org/2023/formulas/mathematics/college/bbxzpgn178mwmrxevt9yd14mqiv42lny5i.png)
Notice that the two events are independent. P(Oil or Hydropower)=0.45.
c)
![\begin{gathered} P(coal)=27\text{percent}=0.27 \\ \Rightarrow P(coal)=0.27 \end{gathered}](https://img.qammunity.org/2023/formulas/mathematics/college/kg8zcu3pyrm7j68pitpvxyh0jg0nvh0sbk.png)
P(Coal)=0.27