SOLUTION: How far from the fulcrum of a teeterboard must an 80-pound boy sit to balance a 50-pound boy who is 4 feet from the fulcrum?

Question 597437: How far from the fulcrum of a teeterboard must an 80-pound boy sit to balance a 50-pound boy who is 4 feet from the fulcrum?
Answer by math-vortex(648) (Show Source): You can put this solution on YOUR website!
Hi, there--
.
To solve this problem, we use the lever principle. A lever can be set up with unequal weights placed at different distances from the fulcrum (balancing point.) Here the lever is a teeterboard.
[I] Define the variables
is the weight of the larger boy = 80 lbs.
is the larger boy's distance from the fulcrum.
is the weight of the smaller boy = 50 lbs.
is the smaller boy's distance from the fulcrum = 4 ft.
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In order for the teeterboard to be balanced, the following equation must be satisfied.

.
Substitute the values you know into the equation and solve for

.
In order to balance the teeterboard, the larger boy must sit 2.5 feet from the fulcrum.
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That's it. Feel free to email me via gmail if the explanation is unclear.
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Ms.Figgy
math.in.the.vortex@gmail.com
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