For this case we have the following data:
Debt in September 2015:
![1.815 * 10^(13)](https://img.qammunity.org/2019/formulas/mathematics/middle-school/8f3lqojfsfczjewh4sastvjx9n1gc6rw0b.png)
Debt in September 2005:
![4.975 * 10^(12)](https://img.qammunity.org/2019/formulas/mathematics/middle-school/3wzk0dlilg6zfg52va22je193gqgk7lnce.png)
The debt in September 2015 can be rewritten as follows:
![18.15 * 10^(12)](https://img.qammunity.org/2019/formulas/mathematics/middle-school/zj8lqoe84k5wbe279as3c0c6to6lv42dod.png)
In this way, we divide the 2015 debt between the 2005 debt, obtaining:
![( 18.15 * 10^(12))/( 4.975 * 10^(12) )=3.65](https://img.qammunity.org/2019/formulas/mathematics/middle-school/7tvv5t1lcuuxt84pg65tzdsawd7kol5x97.png)
Thus, the 2015 debt is 3.65 times larger than the 2005 debt.
Answer:
3.65 times larger