younger tree --- x
middle tree -----y
older tree -------z
x+y+z = 1000 *
time for younger tree to reach age of current middle tree = y - x
at that point:
younger tree --- y
middle tree --- y + y-x = 2y - x
older tree ---- z + y-x
2y-x = z
2y-x = 4x
2y = 5x
y = 5x/2
x + y + z = 1000
x + (5x/2) + (2y - x) = 1000
x + 5x/2 + 10x/2 - x = 1000
15x/2 = 1000
15x = 2000
x = 2000/15 years = 400/3 = appr 133.3 years
y = 5000/15 years = 1000/3 = appr 333.3 years
z = 8000/15 = 1600/3 years = appr 533.3 years
check:
in 200 years the younger will be as old as the middle is now
then the middle would be 533.3, which is the same as the older is now, check!
and which is 4 times the 133.3
the sum of the ages of three redwood trees is exactly one thousand years. when the youngest tree reaches the age of the middle tree, the middle tree will have reached the age of the oldest tree. at that time the middle tree will be four times the current age of the youngest tree. determine the current age of each tree.
1 answer
1 answer