can sumone help me with this fulcrum problem?

Question

Apply the appropriate mathematical operation to solve this fulcrum problem.

Weight 1 = 150 lb.
Weight 2 = 300 lb.
d1 = 15 ft.
d2 =______ft.

Answer 1

you have to balance the torques, which the weight times distance...

weight 1: 150 lb at 15ft = 2250 ft-lb torque.
weight 2: 300lb at d2 ft = 2250ft-lb torque.

so d2 = 2250/300 = 7.5 feet

Answer 2

This is a problem of ratio and proportions. W1 X d1 = W2 x d2 is the relation (The moments need to be equal).

so, d2 = w1.d1/w2 = 150.15/300 = 7.5 feet

Which will just balance the weights.

Answer 3

w1 * d1 = w2 * d2
150 * 15 = 300 * d2
d2 = (150 * 15) / 300 = 7.5

Answer 4

7.5ft.????