A Pole In A LakeMath brain teasers require computations to solve.
There is a pole in a lake. One-half of the pole is in the ground, another one-third of it is covered by water, and 9 ft is out of the water. What is the total length of the pole in ft?
AnswerFraction of pole in the ground = 1/2
Fraction of pole covered by water = 1/3
Fraction of pole in the ground and covered by water = 1/2 + 1/3 = (3 + 2)/6 = 5/6
Fraction of pole out of water = 1 - 5/6 = 1/6
Thus, one-sixth of the pole (out of water) is 9 ft.
So, total length of pole = 54 ft.
It may be noted that:
Length of pole in the ground = 54/2 = 27 ft.
Length of pole covered by water = 54/3 = 18 ft.
Length of pole out of water = 9 ft.
The problem may also be solved by setting up the following equation: x/2 + x/3 + 9 = x
where x denotes the total length of the pole in ft.
The equation may be solved as shown below.
5x/6 + 9 = x
9 = x - 5x/6 = x/6
x/6 = 9 or x = 54.
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