Answer:19. He says that he’s been really tired since several weeks ago. 20. A friend of us is going to pick us up at the airport. 21. I’ve worked like a waiter in the past, but I wouldn’t want to do it again. 22
Explanation:
Answer: 
Explanation:

Multiply by t on both sides.


Now divide by I to isolate t.


Answer:
Humidity is the measure of how much water vapor is in the air.