The fir trees are 9 meters tall and the pine trees are 12 meters tall
Solution:
Let f be the height of one fir tree
Let p be the height of one pine tree
Given that combined height of one fir tree and one pine tree is 21 meters
So we get,
height of one fir tree + height of one pine tree = 21
f + p = 21 ----- eqn 1
Also given that height of 4 fir trees stacked on top of each other is 24 meters taller than one pine tree
height of 4 fir trees stacked on top of each other = 24 + height of one pine tree
4f = 24 + p ---- eqn 2
Let us solve eqn 1 and eqn 2 to find values of "f and "p"
From eqn 1,
f = 21 - p ----- eqn 3
Substitute eqn 3 in eqn 2
4(21 - p) = 24 + p
84 - 4p = 24 + p
-4p - p = 24 - 84
-5p = - 60
Substitute p = 12 in eqn 3
f = 21 - 12 = 9
Summarizing the results:
height of one fir tree = 9 meters
height of one pine tree = 12 meters
