Answer:
8551
Step-by-step explanation:
- The midpoint of two numbers can be found by finding the mean of the two numbers
- Midpoint = 8516 + 8586 / 2
- We clearly see both numbers start with the digits '85' therefore their midpoint will also start with '85'
- The remaining two digits on those two numbers should be added and divided by 2
- ⇒ 16 + 86 / 2 = 102/2 = 51
- Midpoint = 8551