An encounter with multiple CR's involved.

[silverhair2008]

If this question has been asked before please delete this thread.

How do you figure the CR of an encounter that has multiple opponents with different CR's?

Say for example, a CR 7, a CR 5, and 4x Cr 3.

[Tryn]

I normally use the CR / XP equivalent

So simply summ up all the enemies XP (remember to combine multiple monster of the same type to one "CR Monster") and look which CR is nearest.

So in your case
CR 7 3200 XP
CR 5 1600 XP
4x CR 3 = CR 7 = 3200 XP

Total 8000 XP which is around CR 9-10

For XP I normally simply award the XP for each enemy on it's own, so in your case the group would gain (3200 + 1600 + (4x 800))XP = 8000 XP if they managed this encounter.

[silverhair2008]

I wonder how the adventure writers do it?

[Charon's Little Helper]

If you use the official method you end up with essentially the same results.

2 foes of CR X = CR+2

So - 4xCR3 = CR7

added to the base CR7 = CR9

So - CR9 with the CR5 added in - making it just over CR9.