rust8y Posted April 19, 2006 Posted April 19, 2006 Someone please help...I'm stuck on these problems. The fenders (factor enders) of 156 are 1, 2, 3, 4, 6, 8, 9 and that 156 is a 7-fender (that is, it has seven fenders) {1},{2, 12, 52},{3,13},{4},{6, 26, 156},{78},{39} Q1 Find a 1-fender which is composite. Is the answer {1, 11, 121} Q2 Show that a number which has 0 and 9 as fenders has at least four more fenders. Q3 The smallest 10-fender is less than 700. Find it and explain why it is the smallest. Another 7-fender is 460 - its set of fenders is {0, 1, 2, 3, 4, 5, 6}, which is different from the set of fenders of 156. Q4 Find three 9-fenders less than 1000 with different sets of fenders.
matt grime Posted April 19, 2006 Posted April 19, 2006 Q1 is 121 composite? What are its fenders? Have more confidence in your answers. Q3 just make it. If want a fender with 2 and 3 as factors I'd write down 6, the smallest number with 2 and 3 as factors. it also has factors 1 and 6, so i need only figure out how to make it have factors 4,5,7,8,9. More sophisticatedly, you might notice that you only need to worry about prime powers: if it is divisible by 9 and 4 then it is divisible by 2,3,6, 18 and 12.
rust8y Posted April 21, 2006 Author Posted April 21, 2006 (Q2) Still stuck. Show that a number which has 0 and 9 as fenders has at least four more fenders. I've worked out (Q3). The smallest 10-fender is less than 700. I've found 630 but cannot explain why it is the smallest.
Lee Shi Heng Posted May 10, 2006 Posted May 10, 2006 the smallest 10-fender is not 630. it is 540. i chose 1,4,5,27 and multiplied all of them together. The 1 for the 1 fender The 4 for the 2 and 4 fender (even numbers are divisible by 2) The 5 for the 5 and 0 fender (even numbers multiplied by 5 results in a multiple of 10) The 27 for the 3, 6, 7, 8 and 9 fender 27 multiplied by an even number would result it being divisible by 6 and 18. The factors of 6 is 3 and 2, the factors of 18 is 3, 3, 2.
motas11 Posted May 11, 2006 Posted May 11, 2006 hi im a year 7 student doing a extention math program i need answers
motas11 Posted May 11, 2006 Posted May 11, 2006 what is a number that has 0 and 9 as fenders and 4 others
matt grime Posted May 11, 2006 Posted May 11, 2006 experiment, work it out. it really is a question that can be done by working out a few examples (eg, what are the fenders of 24=1.2.3.4, how do they relate to the prime factors) and then thinking about how to make things happen how you want. Ie, you don't just guess, or have 'inspiration': you work out how things behave. If it werew physics, you wouldn't expect to know the outcome of an experiment without doing the experiment, and this is no different.
motas11 Posted May 11, 2006 Posted May 11, 2006 just give me a hint of how to work it out for my self please:confused: .......motas.........
matt grime Posted May 11, 2006 Posted May 11, 2006 the hint is: work hard at it. I know you want more, but this is your work to do for your credit, not for anyone else to do for you.
amosquitoes Posted May 12, 2006 Posted May 12, 2006 no! the smallest 10 fender is 270 work it out yourself.
amosquitoes Posted May 12, 2006 Posted May 12, 2006 write out the working of this, justify the 270 answer
ashennell Posted May 12, 2006 Posted May 12, 2006 I've just tried searching for 'factor enders' and fenders on google and all I can find is this pages and some unrelated stuff. I know factors and prime factors but what are fenders?
matt grime Posted May 12, 2006 Posted May 12, 2006 Exactly what was described in the first post in this thread.
ashennell Posted May 12, 2006 Posted May 12, 2006 The first post, which I have read, gives an example of factor enders not a definition. Perhaps it is possible to determine the definition of a factor ender from this example but I have tried to work it out and can't. If fact it seems to imply that fenders are two differnt things , i.e : The fenders (factor enders) of 156 are 1, 2, 3, 4, 6, 8, 9 and 156 is a 7-fender (that is, it has seven fenders) {1},{2, 12, 52},{3,13},{4},{6, 26, 156},{78},{39} So can someone please just give me a simple definition?
ashennell Posted May 12, 2006 Posted May 12, 2006 Ok, so I worked it out. The last digit of the factor of a number is a fender for that number. Now the questions make sense. Obviously 'maths expert' dosn't imply 'helpful maths expert.'
the tree Posted May 12, 2006 Posted May 12, 2006 Obviously 'maths expert' dosn't imply 'helpful maths expert.'Matt is very helpful when you give him more than 23 minutes to reply. He has every right to watch the Simpsons/eat his dinner/talk to his friends or family/help the students that he gets paid to teach rather than sit in front of a computer awnsering your post.
ashennell Posted May 12, 2006 Posted May 12, 2006 Matt is very helpful when you give him more than 23 minutes to reply. He has every right to watch the Simpsons/eat his dinner/talk to his friends or family/help the students that he gets paid to teach rather than sit in front of a computer awnsering your post. He did reply to my initial question: Exactly what was described in the first post in this thread. Basically telling me to read something I'd already read and that dosn't actually contain a definition.
the tree Posted May 12, 2006 Posted May 12, 2006 Yes, he has a habit of pointing people in the right direction hoping that they start moving. It hones your learning skills, be grateful.
matt grime Posted May 13, 2006 Posted May 13, 2006 The first post states that fenders are factor enders, perhaps grammatically fends would be nicer for factor ends, but we'll allow it to be an agent noun. I'm not sure how much more clearly you need to state that the factor's end is its last digit. Everyone else seemed to have understood that (including me who came into the question with exactly the same prior knowledge of them as you). It then gave an example that demonstrates this: it groups the factors according to their end digit.
blorg glorg Posted May 13, 2006 Posted May 13, 2006 hey rust8y this is from the maths challenge 2006 intermediate booklet and it does say clearly no help from other people unless they r doing the same booklet as u...
blorg glorg Posted May 17, 2006 Posted May 17, 2006 can any1 find an answer to question 2 because u need sumfin to do with 9 but it can also be 19, 29, 39 etc etc... so 3 isnt valid
blorg glorg Posted May 17, 2006 Posted May 17, 2006 can any1 find an answer to question 2 because u need sumfin to do with 9 but it can also be 19, 29, 39 etc etc... so 3 isnt valid
jb4 Posted May 17, 2006 Posted May 17, 2006 Yeah, the answer to question 2 is 190- its factors are 1, 2, 5, 38, 19, 10 Fenders- 1, 2, 5, 8, 9, 0
jb4 Posted May 17, 2006 Posted May 17, 2006 Q4 has got me. I've got 360 but that's it. 720 doesn't work even though it is a 9-fender, it has the same fenders as 360.
Recommended Posts