For this type of problem,
It is stated that the weight of steel is 32.6 lbs per foot
Meaning, every foot of steel beam weighs 32.6.
So 2 feet of steel beam would weigh 32.6 x 2 = 65.2 lbs
and 3 feet will be 32.6 x 3 = 97.8 lbs
Since we have a limit of 5000 lbs which is the capacity of the truck.
We can have an equation :

Where x is the number of foot
Solve the value of x by dividing both sides by 32.6 :

So the answer is 153.37 feet of steel beam