You have to find the difference in height between both checkpoints. To do this just calculate 196 - 52. Checkpoint 5 is 144 (meters?) higher than Checkpoint 2.
namely, what is 1/2 of 3/4, well, is just their product.

Answer: -93.5
Step-by-step explanation:
Average of the two -94+-93/2= -93.5 so thats the midpoint
All possibilities = 9!
possibilities that harry sits at an end = 8! + 8!
possibilities that harry doesn't sit at an end = 9! - 8! -8!