I believe that the answer is C.
The slope and speed of Plane A is 375mph and slope and speed for Plane B is 425 mph... so Plane A travels the fastest
Answer choice B is correct
Try this option:
if x+y=-9 is I (one)
and x+2y=-25 is II (two), then
if II-I, then (x+2y)-(x+y)=-25+9 ⇔ y=-16.
