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# UKMT Volume = Surface Area (Cuboid) Question watch

1. I got 42 as the answer but I felt like my method was really inefficient, this is what I did:

Labeled the two other sides as and .
Surface Area = Volume

And the smaller is the larger is and the first value of that doesn't give a negative value of is , so .

Is this right? If so is it the most efficient method?

2. (Original post by Retsek)

I got 42 as the answer but I felt like my method was really inefficient, this is what I did:

Labeled the two other sides as and .
Surface Area = Volume

And the smaller is the larger is and the first value of that doesn't give a negative value of is , so .

Is this right? If so is it the most efficient method?

It is correct but i'm not sure of a more efficient method.
3. (Original post by Retsek)
x
This is fine but if you want to be more formal, you could say that without loss of generality . Then so as gets larger gets smaller. So now you just need to find the smallest integer that makes an integer as well, which you have done.
4. (Original post by I hate maths)
This is fine but if you want to be more formal, you could say that without loss of generality . Then so as gets larger gets smaller. So now you just need to find the smallest integer that makes an integer as well, which you have done.
Ah see this was where I was going wrong before I had that equation but kept getting a = -6 so went at it from a different angle

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