Question

Let y = safe load in pounds and x = length in feet of a horizontal beam. A constant of proportionality k exists such that . If a beam can hold 2,000 pounds at 15 feet, what is the safe load if the length of the beam is 10 feet?

Answer 1

Answer: The correct answer is 30,000

Answer 2

Proportionality constant would be expressed by

y=kx

We know that at 15ft the beam can hold 2,000lbs. (15, 2000)

y=kx
2000=k(15) = 2000/15=k = 400/3=k. Now with the k solved equation looks like.
y=400/3*x
Plug in the 10 feet for x and solve for y.

y=400/3(10)
y=4000/3
y=1,333.33 lbs