To calculate the growth rate of GDP from year 1 to year 2, you can use the formula for percentage growth:
\[ \text{Growth Rate} = \left( \frac{\text{GDP in Year 2} - \text{GDP in Year 1}}{\text{GDP in Year 1}} \right) \times 100 \]
Substituting the values:
\[ \text{Growth Rate} = \left( \frac{7.5 \text{ billion} - 6 \text{ billion}}{6 \text{ billion}} \right) \times 100 \]
\[ \text{Growth Rate} = \left( \frac{1.5 \text{ billion}}{6 \text{ billion}} \right) \times 100 \]
\[ \text{Growth Rate} = 0.25 \times 100 = 25% \]
So the growth rate of GDP from year 1 to year 2 is 25%.