First, subtract 9 from 29 to find the temperature at 9 A.M. The temperature at 9 A.M. was 20 degrees. The temperature from 5 A.M. doubled to get to the temperature at 9 A.M., so divide 20 by 2. The temperature at 5 A.M. was 10 degrees. The temperature from midnight to 5 A.M. fell 13 degrees, so add 13 to get the temperature at midnight. 13+10=23. It was 23 degrees at midnight.
The problem statement tells you "7 friends were playing basketball".
_____ It appears 5 friends were only playing basketball, 2 friends were playing basketball and having snacks, and 3 friends were only having snacks. Apparently, 10 friends were doing neither of those activities.
