How many beams can go across the bridge

Question

A bridge can support a maximum wight of 7200 lb. A delivery truck carrying metal beams for construction has a weight of 4500 lb. when it is carrying nothing but its driver. Determine the maximum number of beams that can be carried on the truck for a single trip across the bridge given that each beam weighs 205 lbs.

Answer 1

I'm thinking that your teacher may be expecting an equation . If you let x represent the number of beams and each beam weighs 205 lbs, then the total weight of the loaded truck can be represented as 205x + 4500. Since the bridge can only hold 7200 lbs, you can solve

 

205x + 4500 <= 7200 

 

This leads to Deannas answer.

 

VERY IMPORTANT: Let's say using Deanna's arithmetic method, the answer came out to 13.87 instead of 13.17. Many students round off and say 14. Using the inequality that I set up, you would get x <= 13.87 and you would see that 13 is the answer clearly and not make that mistake.

Answer 2

(7200-4500)/205=13.17 or 13 beams.