Question 483212
let weight of boy be x --- 4 feet from fulcrum
weight of girl be y ---12 feet from fulcrum

balances 150*6
4x+12y=150*6..........1


Similarly
8x+6y= 150*6.........2

multiply (1) by -2
we get
-8x-24y=-1800
add this to (2)
-18y=-900
y=50 pounds weight of girl
plug value of y in (2)

8x+300=900
8x=600
x=75 pounds weight of boy

m.ananth@hotmail.ca