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"Simple" Maths Problems - CLOSED!
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Luke Send message Joined: 31 Dec 06 Posts: 2546 Credit: 817,560 RAC: 0 |
Well done Fred!!! Standings: 1. William Rothamel - 13 1/2 Points 2. Fred W - 13 1/2 Points 3. Guido.Man - 8 Points 4. Mr. Kevvy - 7 Points 5. Sarge - 5 1/2 Points 6. Dominique - 5 1/2 Points 7. WinterKnight - 5 Points 8. John McLeod VII - 1 Point 9. Labbie - 1 Point 10. Scary Capitalist - 1/2 Point 11. TBD... And we are tied again... But the tie-breaker is here... Q58 (1/2 a point) : More Prime Number Problems... A : What is the third smallest twin prime? B : What is the fortieth prime number? C : Apply a primality test to 1017, is it prime? D : What is the third "Bell Number prime" E : Apply a primality test to 1361, is it prime? F : How many digits does the 10,000th prime number have, what is it? G : What is the next prime after 109? Luke. - Luke. |
Fred W Send message Joined: 13 Jun 99 Posts: 2524 Credit: 11,954,210 RAC: 0 |
Did you ever get your second answer to Q47? I'm intrigued. F. |
Luke Send message Joined: 31 Dec 06 Posts: 2546 Credit: 817,560 RAC: 0 |
Did you ever get your second answer to Q47? Nope, I Abandoned it, but it's still worth 1/2 a point if any one wants it.. I'll tell you what I'm intrigued about though, the lack of dedicated mathematicians... apart from you and Bill of course ;) Q58 (1/2 a point) : More Prime Number Problems... A : What is the third smallest twin prime? B : What is the fortieth prime number? C : Apply a primality test to 1017, is it prime? D : What is the third "Bell Number prime" E : Apply a primality test to 1361, is it prime? F : How many digits does the 10,000th prime number have, what is it? G : What is the next prime after 109? Luke. - Luke. |
Fred W Send message Joined: 13 Jun 99 Posts: 2524 Credit: 11,954,210 RAC: 0 |
Did you ever get your second answer to Q47? LOL. I'm no dedicated mathematician - I just find numbers and relationships between them absolutely fascinating. F. |
William Rothamel Send message Joined: 25 Oct 06 Posts: 3756 Credit: 1,999,735 RAC: 4 |
Do you know what is really sad is the fact that Here on the SETI science and non science boards, all but a few posts on average are days old. The Cafe does very well but I am concerned that science has such a low following.Did you ever get your second answer to Q47? On Q 47. Is the other solution also using 4 weights (or a minimum number of weights) and a single weighing)--if not there can be an infinite number of solutions. Consider the following: With a single weight --say a one pounder--he can hang this weight at 40 different marks along one side of the balance to correspond with each of 40 pounds. Bill. |
William Rothamel Send message Joined: 25 Oct 06 Posts: 3756 Credit: 1,999,735 RAC: 4 |
here they are: Too much work for only a half mark. Q58 (1/2 a point) : More Prime Number Problems... A : What is the third smallest twin prime?--17 B : What is the fortieth prime number?--173 C : Apply a primality test to 1017, is it prime?--is not prime D : What is the third "Bell Number prime"--877 E : Apply a primality test to 1361, is it prime? --yes it's prime F : How many digits does the 10,000th prime number have, what is it? --6 digits, 104729 G : What is the next prime after 109?--113 Luke. [/quote] |
Fred W Send message Joined: 13 Jun 99 Posts: 2524 Credit: 11,954,210 RAC: 0 |
Do you know what is really sad is the fact that Here on the SETI science and non science boards, all but a few posts on average are days old. The Cafe does very well but I am concerned that science has such a low following. Couldn't agree more, Bill (on the sad part). On Q47, the question does say "the least possible number of weights" and if my answer is a correct one, then 4 is the "least possible number of weights". Hence there must be another answer using 4 weights, but I can't get it ATM. F. |
Luke Send message Joined: 31 Dec 06 Posts: 2546 Credit: 817,560 RAC: 0 |
Bill, well done... Sorry about the worthlessness of the question, it was originally only going to be A, B, C sub-questions... Fred - To Q47, the first set of weights needed was 1,3,9,27 lbs.... the next set need 5 weights... Bill, you are also right about the number of posters in the cafe but not the science forum, on average the 50th oldest thread in the Cafe had its last post 1/2 days ago, while in the science forum the 50th oldest thread was 39 days old... Standings: 1. William Rothamel - 14 Points 2. Fred W - 13 1/2 Points 3. Guido.Man - 8 Points 4. Mr. Kevvy - 7 Points 5. Sarge - 5 1/2 Points 6. Dominique - 5 1/2 Points 7. WinterKnight - 5 Points 8. John McLeod VII - 1 Point 9. Labbie - 1 Point 10. Scary Capitalist - 1/2 Point 11. TBD... Q59 : (1 Point) If 6 boys fill 6 notebooks in 6 weeks and 4 girls fill 4 notebooks in 4 weeks, how many notebooks will a class of 12 boys and 12 girls fill in 12 weeks? Luke. - Luke. |
William Rothamel Send message Joined: 25 Oct 06 Posts: 3756 Credit: 1,999,735 RAC: 4 |
Q59 answer is 60 |
Dr Who Fan Send message Joined: 8 Jan 01 Posts: 3218 Credit: 715,342 RAC: 4 |
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Luke Send message Joined: 31 Dec 06 Posts: 2546 Credit: 817,560 RAC: 0 |
Bill wins Question 59... with the answer 60... and a good post by Dr. Who Fan (lol)... Standings: 1. William Rothamel - 15 Points 2. Fred W - 13 1/2 Points 3. Guido.Man - 8 Points 4. Mr. Kevvy - 7 Points 5. Sarge - 5 1/2 Points 6. Dominique - 5 1/2 Points 7. WinterKnight - 5 Points 8. John McLeod VII - 1 Point 9. Labbie - 1 Point 10. Scary Capitalist - 1/2 Point 11. TBD... Q60 : (1 Point) If we set out by ranks of 10, we will be one short. We will also be one short if we set out by ranks of 9, 8, 7, 6, 5, 4, 3, and even 2. Yet there are fewer than 5000 participants. How many are we? Q61 : (1/2 a point) what is the square root of 2547? Luke. - Luke. |
Fred W Send message Joined: 13 Jun 99 Posts: 2524 Credit: 11,954,210 RAC: 0 |
Bill wins Question 59... with the answer 60... Q60: 2519 F. |
William Rothamel Send message Joined: 25 Oct 06 Posts: 3756 Credit: 1,999,735 RAC: 4 |
I just woke up for a few minutes. Fred recognized the monkey problem in different guise. |
Fred W Send message Joined: 13 Jun 99 Posts: 2524 Credit: 11,954,210 RAC: 0 |
I just woke up for a few minutes. Monkey problem?? Just Googled it and it is quite interesting. However, my method was brute force and ignorance (of the said Monkey Problem); i.e. - Had to end in a 9 - Sum of the digits + 1 divisible by 9 - Work through those testing for (almost) divisibility by 8 and then by 7 etc. F. NB Any calculator will give the answer to Q61 to n dp's. The number of dp's is not specified - I trust you are expecting to see the working for this one, Luke? |
William Rothamel Send message Joined: 25 Oct 06 Posts: 3756 Credit: 1,999,735 RAC: 4 |
I just woke up for a few minutes. This answer is the same as to the second monkey problem where they were always one coconut short. The trick here is to recognize this type of problem as one of finding the least common multiple. You can do this with an algorithm but as I stated in my solution there are tools on the internet for finding these multiples. |
Fred W Send message Joined: 13 Jun 99 Posts: 2524 Credit: 11,954,210 RAC: 0 |
Yes, I found some after the event ;( As ever, a new day - something else to learn :)) F. |
Luke Send message Joined: 31 Dec 06 Posts: 2546 Credit: 817,560 RAC: 0 |
Yup, well done to Fred! I learn something new every day ;) Standings: 1. William Rothamel - 15 Points 2. Fred W - 14 1/2 Points 3. Guido.Man - 8 Points 4. Mr. Kevvy - 7 Points 5. Sarge - 5 1/2 Points 6. Dominique - 5 1/2 Points 7. WinterKnight - 5 Points 8. John McLeod VII - 1 Point 9. Labbie - 1 Point 10. Scary Capitalist - 1/2 Point 11. TBD... Fred & Bill are leaving everyone else behind in their smoke trail! I though this one would have been solved by now!... Q61 : (1/2 a point) what is the square root of 2547? (no calculators for this one please...) More later.... Luke. - Luke. |
Fred W Send message Joined: 13 Jun 99 Posts: 2524 Credit: 11,954,210 RAC: 0 |
Yup, well done to Fred! I learn something new every day ;) Q61: By iterative testing starting at 50.5, then 50.4, then 50.45, then 50.47, the answer (rounded to 2 d.p's) is 50.47. I then got bored and looked it up, getting 50.46781152378217 (when rounded to 14 d.p's). F. |
Luke Send message Joined: 31 Dec 06 Posts: 2546 Credit: 817,560 RAC: 0 |
Close Enough Fred!, and again you tie with Bill... Standings: 1. William Rothamel - 15 Points 2. Fred W - 14 1/2 Points 3. Guido.Man - 8 Points 4. Mr. Kevvy - 7 Points 5. Sarge - 5 1/2 Points 6. Dominique - 5 1/2 Points 7. WinterKnight - 5 Points 8. John McLeod VII - 1 Point 9. Labbie - 1 Point 10. Scary Capitalist - 1/2 Point 11. TBD... Q62 : (1 Point) Thirteen per cent of the people in a certain town have unlisted phone numbers. You select three hundred names at random from the phone book. What is the expected number of people who will have unlisted numbers? Luke. - Luke. |
Philadelphia Send message Joined: 12 Feb 07 Posts: 1590 Credit: 399,688 RAC: 0 |
Close Enough Fred!, and again you tie with Bill... None, since they're obviously listed in the phone book. |
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