It's an 11% increase. To find this, you have to subtract 85 from 94.35 and then you divide that difference by the original amount. In this case it's 85. After that, you get .11. Then you just turn it into a percent.
The formula of a midpoint of a segment AB:

We have:
H(10; 1); K(4; 7)
substitute:

Answer: (7, 4)
Answer: yes there is a limit
That is complicated but, I'll go with 15.