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# AQA D1 Linear Programming constraints? watch

1. I'm stuck on Linear programming constraints in decision 1, I have no idea how the constraints thing works or how to answer questions using it, here is the constraints part I don't understand:

I have no idea why the machines time constraint is 2x + 3y < 30
Why would it be 2x + 3y < 30, I understand they got the 30 hours from the machine time but 2x + 3y all together = to 13 hours of machine time, why such a random number to make a constraint less than 30 on, I have no idea how they came up with this. Can anyone explain this to me i'm struggling
2. (Original post by Sayless)
I'm stuck on Linear programming constraints in decision 1, I have no idea how the constraints thing works or how to answer questions using it, here is the constraints part I don't understand:

I have no idea why the machines time constraint is 2x + 3y < 30
Why would it be 2x + 3y < 30, I understand they got the 30 hours from the machine time but 2x + 3y all together = to 13 hours of machine time, why such a random number to make a constraint less than 30 on, I have no idea how they came up with this. Can anyone explain this to me i'm struggling
Remember that x is the number of type A machines that are made and y is the number of type B machines that are made. So 2x for example could represent 2 hours spent on the machine.

30 hours is the total machine hours available.

How many machine hours does type A take to make per unit? How about type B?

So 30 hours are available, and if x represents the number of type A units made and y the number of type B units, and have the whole equation with time as their units (not that it matters but to understand) then the inequality becomes 2 hours * x (number of type A units made) + 3 hours * y (number of type B units made) and they have to be less than or equal to 30.

So you could concentrate all of your time on 15 type A's and 0 type B's (giving 15 * 2 + 0 * 3 = 30) or the other way around.
3. (Original post by SeanFM)
Remember that x is the number of type A machines that are made and y is the number of type B machines that are made. So 2x for example could represent 2 hours spent on the machine.

30 hours is the total machine hours available.

How many machine hours does type A take to make per unit? How about type B?

So 30 hours are available, and if x represents the number of type A units made and y the number of type B units, and have the whole equation with time as their units (not that it matters but to understand) then the inequality becomes 2 hours * x (number of type A units made) + 3 hours * y (number of type B units made) and they have to be less than or equal to 30.

So you could concentrate all of your time on 15 type A's and 0 type B's (giving 15 * 2 + 0 * 3 = 30) or the other way around.
AHhh i get it now ,so the numbers 2 and 3, represent the machine time hours.
that makes sense now thanks i just thought they meant the amount of type A or something idk thanks
4. Hi
Dose every school do A/L maths D1?
Thank you

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