# Probabilty practice

#### Maygyver

10+ Year Member
5+ Year Member
Does anyone know a website that has some pretty simple DAT-like probability problem sets?

#### akeurogh

7+ Year Member
why don't you try the math section of the destroyer, it has a bunch!

#### Maygyver

10+ Year Member
5+ Year Member
why don't you try the math section of the destroyer, it has a bunch!
Yeah, I've gone through them all, I was just hoping for a place with a bunch of permutation/combination stuff because I'm still having trouble figuring out when to use what and it's too easy to go back over problems that I already figured out which one to use.

#### dentalWorks

##### Nights Watchmen
7+ Year Member
Here is a simple rule that always helps me with simple probabilities.

The probability of event A AND event B happening (you need to multiply)

The probability of event A OR event B happening (you need to add)

#### Maygyver

10+ Year Member
5+ Year Member
Here is a simple rule that always helps me with simple probabilities.

The probability of event A AND event B happening (you need to multiply)

The probability of event A OR event B happening (you need to add)
What about for permutations/combinations? Is just knowing that when order matters you do n!/k!(n-k)! and when order doesn't matter you use n!/(n-k)! enough do you think?

#### dentalWorks

##### Nights Watchmen
7+ Year Member
What about for permutations/combinations? Is just knowing that when order matters you do n!/k!(n-k)! and when order doesn't matter you use n!/(n-k)! enough do you think?
For me personally, most of my DAT questions were of the simple "AND" / "OR" types. I think I had only 1 (or 2) that had to do with ordering, and I remember the first thing I did when I read it was I picked B and moved on to the next question...did not wanna waste time and still end up not getting it right

#### Maygyver

10+ Year Member
5+ Year Member
For me personally, most of my DAT questions were of the simple "AND" / "OR" types. I think I had only 1 (or 2) that had to do with ordering, and I remember the first thing I did when I read it was I picked B and moved on to the next question...did not wanna waste time and still end up not getting it right
Sounds good. Thanks!