filter rows based on filtering two different columns
 

Hello,
I am trying to print out rows that would match a particular filtering criteria on two columns:
Simple matrix:
sample1 0 0 4
sample2 0 0 10
sample3 0 0 15
sample4 0 0 20
sample5 3 2 3

I would like to print out rows where column 2==3 and column 4 <20.
This will print out the last row only.

is this possible in awk?
I understand how to apply one column filter but how to apply a two column filter:
this works so far;
awk '$4<20 {print $0}' simplematrix.txt

I tried:
awk '$4<20 & $2==3 {print $0}' simplematrix.txt
and I get a syntax error.

Anyone help??

Thanks a bunch! Just found the correct syntax on the web too. Appreciate the fast reply!