Jerome has 20 classmates on the list, and has half as many out of school friends on there so he has 20/2=<<20/2=10>>10 out of school friends on the contact list
He has 2 parents and 1 sister on the contact list, for 2+1= <<2+1=3>>3 family members on the contact list.
Adding the classmates, out of school friends and family members together we get 20+10+3=<<20+10+3=33>>33 people on his contact list
#### 33