Let <em>a</em> denote the airplane's speed in still air, and <em>w</em> the windspeed.
When the plane flies against the wind, it can travel an average speed of
(4500 km) / (6 h) = 750 km/h
so that
<em>a</em> - <em>w</em> = 750 km/h
Flying with the wind, it moves at a speed of
(2910 km) / (3 h) = 970 km/h
so that
<em>a</em> + <em>w</em> = 970 km/h
Add the two equations to eliminate <em>w</em> and solve for <em>a</em> :
(<em>a</em> - <em>w</em>) + (<em>a</em> + <em>w</em>) = 750 km/h + 970 km/h
2<em>a</em> = 1720 km/h
<em>a</em> = 860 km/h
Subtract them to eliminate <em>a</em> and solve for <em>w</em> :
(<em>a</em> - <em>w</em>) - (<em>a</em> + <em>w</em>) = 750 km/h - 970 km/h
-2<em>w</em> = -220 km/h
<em>w</em> = 110 km/h
You divide 15 by 2 (D is the answer)
Answer:
It has 10 three-point questions and 14 five-point questions
Step-by-step explanation:
Substitution (look it up it takes a long time to explain lol)
Geometric figure is: line.
First of all, we know a quality of all interior angles of a triangle, they should add to 180 degrees.
Does 50+50+80 degrees give 180 degrees?
100+80=180 degrees
Therefore, yes, it is possible to draw a triangle with the angle measures given to be 50, 50 and 80 degrees.
Hope I helped :)
