Usually the next step in describing a situation mathematically is to give both our know and unknown objects variable names.
For example, we can give "the number of pounds that Jim's skidoo can take" the variable name MaximumGearWeight. In this case, we know that the value of the variable MaximumGearWeight is 243 (pounds) because Jim has said that that's the maximum number of pounds of gear his skidoo can take.
MaximumGearWeight = 243
We can give the number of pounds of gear each individual person can take a variable name as well. How about GearWeightPerPerson? Of course, the choice of variable name is up to you.
In this case, the variable name GearWeightPerPerson is performing a similar function to that of the variable name "TheCandyInMyHand" from section 3.4. In that case, you didn't yet know what candy was in your hand, because you hadn't looked at it yet, but you knew it was a type of candy and could still give it a variable name. In this case, you don't know the actual number of pounds of gear each person can take, but you know it is an amount of weight in pounds and you can give this unknown amount a variable name.
GearWeightPerPerson = ? (we don't know yet)
We could also give variable names to the weight of each person's gear. For example, JimGearWeight for the weight of Jim's gear, JaneGearWeight for the weight of Jane's gear and ScottGearWeight for the weight of Scott's gear.
Usually it's better to come up with lots of variable names, for all of the important objects in the problem, even if you don't end up using them all when you are solving the problem.