Answer:


Step-by-step explanation:
Lets call
the the still-air speed of the plane and
the speed of the wind. On the first part the speed of the plane relative to the ground will be
, and on the second part it will be
.
We know that the distance d=400 miles on the first and second parts are the same, so by the definition of velocity we will have:


Or:


Adding both equations:


Which for our values is:

If instead of adding, we substact, we would have:


Which for our values is:

Well, 15% of 60 is 9 so now you have to create a model :)
M = 135/19 and n = -5/19
You have to give them like terms so that when you eliminate they cancel out and you can solve. The easiest way to do so is by multiplying the top equation by -4 and the bottom by 3.
500-360+350-490 answer is 490
Answer:
D
Step-by-step explanation: