How do I write formula to calculate outcome of event?

Brilliant Construct community, need help coming up with a way to calculate outcome of an event. In the game I'm working to develop, there are a set of factors that can impact the success of an event (small sampling of factors); smarts, speed and ability. The event being a player disarming a bomb.

• smart - 10% increase in success
• speed - 5% increase in success
• ability - 15% increase in success

I've been checking online for the formula on how to determine if the disarming was successful. I'll admit up front I have no idea how this works as I'm used to writing formulas in Excel so any help you can provide would be much appreciated.

You pretty much want to draw a random integer number between 0 and 100.

The expression to do so is int(random(101))

And you want to compare this number to the percentages of your skills.

So let's assume we have a 20% base chance disarming the bomb.

As I'm smart, it goes up to 30%

Is my random number less or equal 30 ?

If so, I have disarmed the bomb. Otherwise, it blew up in my face.

The random number likely has to be assigned to a variable (local or global) and tested against a value made up of the base chance and the addition of skills value to it.

Global var : randNum

On user action

- Set randNum to int(random(101))

sub-event

Compare randNum is less or equal baseChance + smart + speed + ability

-> Win

Else

-> Explosion

Very well written and explained. Thank you!!

Going to test it and post back any questions I come across.