MISSING LINK XCIX

FBI
Credit: NPR Weekend Edition Sunday Puzzle
December 13, 2015
Will Shortz

Each trio of words below shares a Missing Link - that is, its members have something in common, obvious or not. For example, RIVERS, NOSES, & VIOLINS can all have BRIDGES.

1)
Fast
Back
Inside

2)
Floor
Bulletin
Ironing

3)
Flash
Birthday
Index

4)
Fun
Brokerage
Ice

5)
Family
Best
Invisible

6)
Florida
Backspace
Ignition

7)
First
Birth
Interest

Answers:

1. Track
2. Board
3. Card
4. House
5. Man
6. Key
7. Rate