NA 
Four numbers are written in a row. The average of the first two is $21$, the average of the middle two is $26$, and the average of the last two is $30$. What is the average of the first and last of the numbers? 
1. $$24$$ 
2. $$25$$ 
3. $$26$$ 
4. $$27$$ 
5. $$28$$ 