To determine how many weeks it will take Jason to collect coins from all 195 countries, we can start by calculating how many more countries he needs to collect coins from.
Jason currently has coins from 99 countries. The total number of countries is 195, so the number of additional countries he needs to collect is:
\[ 195 - 99 = 96 \text{ countries} \]
Jason plans to add 4 new countries to his collection each week. To find out how many weeks (w) it will take him to collect the remaining 96 countries, we can use the formula:
\[ w = \frac{\text{Number of additional countries}}{\text{Countries added per week}} = \frac{96}{4} \]
Now, calculating the number of weeks:
\[ w = \frac{96}{4} = 24 \text{ weeks} \]
Therefore, it will take Jason 24 weeks to collect coins from all 195 countries.