The orthocenter is at (1, 5) hope this helps. If you need an explanation then ask me. Hope it helps :)
The answer is c. It would be -1/2
Simple: 800( 1 + 0.10*5) = 800(1.5) = $1200
Compound: 800(1+0.095/12)^(12*5) = $1284
Compounding at 9.5% will give you the better investment.
One third is a rational number....since it can be written in p/q form(1/3)