Australian Maths Competition Past Paper Help (1 Viewer)

[andrew12678]

Hi

I have attached links for Q25-30 of an AMC past paper, any help with any of the questions would be greatly appreciated.

http://postimg.org/image/u89c7sbht/
http://postimg.org/image/kt3um3tmd/


Andrew

 

[braintic]

I've just looked at Q25.
I don't have enough time to give it a lot of thought.
Nevertheless, you should be able to eliminate C and E immediately without even considering differences.
And D can be eliminated quite quickly with only a brief consideration of differences.
So it is A or B.

 

[RealiseNothing]

2 -> 4 -> 3 -> 6 -> 1 -> 5

 

[RealiseNothing]

2 -> 4 -> 3 -> 6 -> 1 -> 5

To see this is quite easy.

Notice that you have 5 "differences" which must either 1, 2, 3, 4, or 5. You must use all five of these differences.

Now the only way you can have a difference of five is if 1 and 6 are next to each other. So denote this by (1,6) - 1 and 6 must be adjacent.

Now we must a difference of four, which can be done by either having 1 and 5 together, or 2 and 6 together.

Hence we have only two possibilities already - (1,5,6) or (1,2,6). These must be the last three numbers then. Hence the sum of the last three digits is either 1+2+6=9 or 1+5+6=12.

Hence answer is A since 9 is not an option.

 

[yo_yo]

Good luck to all!

 

[turnerloos]

Good luck to all!

You too brahh

 

[iStudent]

This maths comp sigh. I knew how to do the majority of 1-25 but 25-30 I'm always 100% clueless

 

[yo_yo]

This maths comp sigh. I knew how to do the majority of 1-25 but 25-30 I'm always 100% clueless

Write 25-30 to try to solve.

 

[QZP]

i thought i was playing the lotto in those last 5 questions

 

[yo_yo]

i thought i was playing the lotto in those last 5 questions

If anyone has conditions please write them down, we will try to solve them together.

 

[Speed6]

RealiseNothing has got it.

 

[yo_yo]

I only remember 26 vaguely ish
What is the greatest 3 digit number such that it is equal to the sum of the the hundredth number, the square of the tenth number and the cube of the single digit.

This division is what?

 

[VikeStep]

EDIT: Removed posts since not all people have done the comp yet

 

[QZP]

There might have been people who have not done the exam yet (postponed) lol

 

[iStudent]

No, we can't have more than 2 vowels in a row. But we can have them at the start and end. That was what the question asked. (there were no restrictions on start and end for vowels).

edit: deleted my other posts because people haven't done the competition yet