Answer:
Fir trees are 9 meters and the pine trees are 12 meters tall.
Explanation:
Let the height of the fir tree = x and the height of the pine tree = y (in meters).
It is given that the combined height of both the trees is 21 meters.
That is,
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Also, the height of 4 fir trees is 24 meters more than that of the pine tree.
That is,
i.e.
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So, we get the system of equations,
x+y=21
4x-y=24
Adding both the equations, gives us,
5x = 45 i.e. x= 9.
So, x+y=21 ⇒ y= 21 - x ⇒ y= 21 - 9 ⇒ y= 12.
Thus, the fir trees are 9 meters tall and the pine trees are 12 meters tall.