The Consumer Price Index (CPI) can be calculated using the following formula:
\[ \text{CPI} = \left( \frac{\text{Cost of Basket in Current Year}}{\text{Cost of Basket in Base Year}} \right) \times 100 \]
In this case, the base year is Year 1, and the cost of the basket in Year 1 is $50. The cost of the basket in Year 3 is $55.
Using the formula, we can calculate the CPI for Year 3:
\[ \text{CPI in Year 3} = \left( \frac{55}{50} \right) \times 100 = 1.1 \times 100 = 110.0 \]
Thus, the value of the CPI in Year 3 is:
d. 110.0.