Reach 100 points then add 15 sec

Hi there!
Ive created a small game where i pick up score that gives me 20p. They spawn randomly and everything works fine. I have a 30 sec countdown,

im trying to script that each 100p i reach it will add 15 sec to my timer. So basically when picking up 5 pickups (20p each) ill get 15 sec when having 100p. And when i reach 200p 15 new sec, 300p adds 15 sec and so on.

Some one who can help me?

It would be something along the lines of:

Thank you! It works now!