Answer:
She can advertise for 10 days 
Explanation:
Here, we want to know for how long can Jackie advertise if she decides to buy a 4-line ad which will run for three days.
The total money she has or she wants to spend is $15. 
Now if $4.35 will run for 3 days 
then $15 will run for x days 
4.35 * x = 15 * 3
4.35x = 45 
x = 45/4.35
x = 10.34 which is approximately 10 to the nearest whole number