Electricity circuit problem
by eagle2010, Apr 6, 2025, 4:42 AM
In the diagrams below, switches A, B and C work independently of each other. The probability that any given switch is closed is 0.9. Current can only flow through a switch if it is closed. Work out the probability that the current can flow from on end to the other end of the circuit.
Diagrams attached below
Diagrams attached below
Math Problem I cant figure out how to do without bashing
by equalsmc2, Apr 6, 2025, 12:29 AM
Hi,
I cant figure out how to do these 2 problems without bashing. Do you guys have any ideas for an elegant solution? Thank you!
Prob 1.
An RSM sports field has a square shape. Poles with letters M, A, T, H are located at the corners of the square (see the diagram). During warm up, a student starts at any pole, runs to another pole along a side of the square or across the field along diagonal MT (only in the direction from M to T), then runs to another pole along a side of the square or along diagonal MT, and so on. The student cannot repeat a run along the same side/diagonal of the square in the same direction. For instance, she cannot run from M to A twice, but she can run from M to A and at some point from A to M. How many different ways are there to complete the warm up that includes all nine possible runs (see the diagram)? One possible way is M-A-T-H-M-H-T-A-M-T (picture attached)
Prob 2.
In the expression 5@5@5@5@5 you replace each of the four @ symbols with either +, or, or x, or . You can insert one or more pairs of parentheses to control the order of operations. Find the second least whole number that CANNOT be the value of the resulting expression. For example, each of the numbers 25=5+5+5+5+5 and 605+(5+5)×5+5 can be the value of the resulting expression.
Prob 3. (This isnt bashing I don't understand how to do it though)
Suppose BC = 3AB in rectangle ABCD. Points E and F are on side BC such that BE = EF = FC. Compute the sum of the degree measures of the four angles EAB, EAF, EAC, EAD.
P.S. These are from an RSM olympiad. The answers are
I cant figure out how to do these 2 problems without bashing. Do you guys have any ideas for an elegant solution? Thank you!
Prob 1.
An RSM sports field has a square shape. Poles with letters M, A, T, H are located at the corners of the square (see the diagram). During warm up, a student starts at any pole, runs to another pole along a side of the square or across the field along diagonal MT (only in the direction from M to T), then runs to another pole along a side of the square or along diagonal MT, and so on. The student cannot repeat a run along the same side/diagonal of the square in the same direction. For instance, she cannot run from M to A twice, but she can run from M to A and at some point from A to M. How many different ways are there to complete the warm up that includes all nine possible runs (see the diagram)? One possible way is M-A-T-H-M-H-T-A-M-T (picture attached)
Prob 2.
In the expression 5@5@5@5@5 you replace each of the four @ symbols with either +, or, or x, or . You can insert one or more pairs of parentheses to control the order of operations. Find the second least whole number that CANNOT be the value of the resulting expression. For example, each of the numbers 25=5+5+5+5+5 and 605+(5+5)×5+5 can be the value of the resulting expression.
Prob 3. (This isnt bashing I don't understand how to do it though)
Suppose BC = 3AB in rectangle ABCD. Points E and F are on side BC such that BE = EF = FC. Compute the sum of the degree measures of the four angles EAB, EAF, EAC, EAD.
P.S. These are from an RSM olympiad. The answers are
32, 17, 135
This post has been edited 1 time. Last edited by equalsmc2, Today at 12:33 AM
Reason: wrong answer
Reason: wrong answer
Math and AI 4 Girls
by mkwhe, Apr 5, 2025, 11:24 PM
Hey everyone!
The 2025 MA4G competition is now open!
Apply Here: https://xmathandai4girls.submittable.com/submit
Visit https://www.mathandai4girls.org/ to get started!
Feel free to PM or email mathandai4girls@yahoo.com if you have any questions!
The 2025 MA4G competition is now open!
Apply Here: https://xmathandai4girls.submittable.com/submit
Visit https://www.mathandai4girls.org/ to get started!
Feel free to PM or email mathandai4girls@yahoo.com if you have any questions!
STATE SOLUTIONS AND STUFF DROPPED!!!
by Soupboy0, Apr 4, 2025, 5:44 PM
FTW tournament!
by evt917, Apr 3, 2025, 9:34 PM
Since all FTW tournaments have dramatically failed, I'm trying a different format. Here is how it works:
1. Type \signup{your rating (type 800 for unrated)}
2. You will pick who you want to play with. You can play if they accept your challenge. So basically the players run everything. Just don't intentionally play low-rated people. Also try to play different people so everyone gets a chance to play! ONLY two player games.
3. If you win, you get 2 points. Ties get one point, and losses get zero.
4. I do not know everybody's time preferences. Because so, I will announce in advance which two players will be playing, so they themselves can organize a game themselves. Remember, THE PLAYERS ARE ORGANIZING THE GAMES THEMSELVES!!! The format is up to them, but please make the time control at least 20 seconds. Please announce the results of the game here so i can update the scoreboard. Games can be unrated.
recommended format if you cannot decide
5. The tournament goes on until april 10th! Extremely long, right? Note that you can still signup after the first games has started, but you will have a disadvantage because some people who signed up as soon as the tournament started already has points.
6. Once you are done with your game, you can find a new opponent and play with them if they want. Note that you must play opponents within the tournament. If you play in the tournament, you are automatically signed up. Have fun!
Questions and Answers
All signups and ratings
LIVE LEADERBOARD:
1st place: 47 points | 17W 3L 3T | Yrock
2nd place: 14 points | 6W 3L 2T | jb2015007
3rd place: 5 points | 2W 8L 1T | sadas123
4th place: 4 points | 1W 2L 0T | IcyFire500
5th place: 0 points | 0W 1L 0T | NS0004
1. Type \signup{your rating (type 800 for unrated)}
2. You will pick who you want to play with. You can play if they accept your challenge. So basically the players run everything. Just don't intentionally play low-rated people. Also try to play different people so everyone gets a chance to play! ONLY two player games.
3. If you win, you get 2 points. Ties get one point, and losses get zero.
4. I do not know everybody's time preferences. Because so, I will announce in advance which two players will be playing, so they themselves can organize a game themselves. Remember, THE PLAYERS ARE ORGANIZING THE GAMES THEMSELVES!!! The format is up to them, but please make the time control at least 20 seconds. Please announce the results of the game here so i can update the scoreboard. Games can be unrated.
recommended format if you cannot decide
45 seconds
Time scoring
8 questions
Time scoring
8 questions
5. The tournament goes on until april 10th! Extremely long, right? Note that you can still signup after the first games has started, but you will have a disadvantage because some people who signed up as soon as the tournament started already has points.
6. Once you are done with your game, you can find a new opponent and play with them if they want. Note that you must play opponents within the tournament. If you play in the tournament, you are automatically signed up. Have fun!
Questions and Answers
Is there prizes?
Yes, the fact that you don't have to pay is nice enough. donations are strongly encouraged though.
Yes, the fact that you don't have to pay is nice enough. donations are strongly encouraged though.
All signups and ratings
1. jb2015007 (1274) [14 points, 6W 3L 2T]
2. NS0004 (1117)
3. EaZ_Shadow (1377)
4. IcyFire500 (1237) [4 points, 1W 3L 0T]
5. Bigtree (800)
6. Yrock (1502) [41 points, 14W 1L 3T]
7. Leeoz (1189)
8. derekwang2048 (1287)
9. sadas123 (1368) [5 points, 2W 8L 1T]
10. Robert00 (1211)
11. Existing_Human1 (1166)
12. giratina3 (1331)
13. BAM10 (800)
14. NS0004 (unknown) [0 points, 0W 1L 0T]
15. K124659 (1274)
16. mathnerd_101 (1670)
17. MathCosine (1351)
18. MajesticCheese (unknown)
19. PikaPika999 (1353)
2. NS0004 (1117)
3. EaZ_Shadow (1377)
4. IcyFire500 (1237) [4 points, 1W 3L 0T]
5. Bigtree (800)
6. Yrock (1502) [41 points, 14W 1L 3T]
7. Leeoz (1189)
8. derekwang2048 (1287)
9. sadas123 (1368) [5 points, 2W 8L 1T]
10. Robert00 (1211)
11. Existing_Human1 (1166)
12. giratina3 (1331)
13. BAM10 (800)
14. NS0004 (unknown) [0 points, 0W 1L 0T]
15. K124659 (1274)
16. mathnerd_101 (1670)
17. MathCosine (1351)
18. MajesticCheese (unknown)
19. PikaPika999 (1353)
LIVE LEADERBOARD:
1st place: 47 points | 17W 3L 3T | Yrock
2nd place: 14 points | 6W 3L 2T | jb2015007
3rd place: 5 points | 2W 8L 1T | sadas123
4th place: 4 points | 1W 2L 0T | IcyFire500
5th place: 0 points | 0W 1L 0T | NS0004
This post has been edited 50 times. Last edited by evt917, Yesterday at 6:56 PM
FTW
L
real math problems
by Soupboy0, Mar 25, 2025, 11:40 PM
Ill be posting questions once in a while. Here's the first question:
What fraction of numbers from
to
have the digit
and are divisible by
?
What fraction of numbers from




The daily problem!
by Leeoz, Mar 21, 2025, 10:01 PM
Every day, I will try to post a new problem for you all to solve! If you want to post a daily problem, you can! 
Please hide solutions and answers, hints are fine though!
The first problem is:
Past Problems!
Answer
Answer
Answer
Answer
Answer
Answer
Answer
Answer

Please hide solutions and answers, hints are fine though!

The first problem is:
March 21st Problem wrote:
Alice flips a fair coin until she gets 2 heads in a row, or a tail and then a head. What is the probability that she stopped after 2 heads in a row? Express your answer as a common fraction.
Past Problems!
March 21st Problem wrote:
Alice flips a fair coin until she gets 2 heads in a row, or a tail and then a head. What is the probability that she stopped after 2 heads in a row? Express your answer as a common fraction.

March 22nd Problem wrote:
In a best out of 5 math tournament, 2 teams compete to solve math problems, with each of the teams having a 50% chance of winning each round. The tournament ends when one team wins 3 rounds. What is the probability that the tournament will end before the fifth round? Express your answer as a common fraction.

March 23rd Problem wrote:
The equations of
and
intersect at the point
. What is the value of
?





March 24th Problem wrote:
Anthony rolls two fair six sided dice. What is the sum of all the different possible products of his rolls?

March 25th Problem wrote:
If
, find the value of
.



March 26th Problem wrote:
There is a group of 6 friends standing in line. However, 3 of them don't want to stand next to each other. In how many ways can they stand in line?

March 27th Problem wrote:
Two real numbers,
and
are chosen from 0 to 1. What is the probability that their positive difference is more than
?




March 28th Problem wrote:
What is the least possible value of the expression
?


This post has been edited 4 times. Last edited by Leeoz, Mar 30, 2025, 12:08 AM
Have you taken the AMC 10 test before?
by aadimathgenius9, Jan 5, 2025, 12:42 AM
Loading poll details...
Have you taken the AMC 10 test before?
EMC Wrangle Favorites #1
by peace09, Jul 28, 2022, 6:00 PM
Is it possible to dissect an isosceles right triangle into multiple similar triangles such that none of them are congruent? If so, provide an example. If not, prove it is impossible.
This post has been edited 1 time. Last edited by peace09, Aug 2, 2022, 2:25 PM
L
♪ i just hope you understand / sometimes the clothes do not make the man ♫ // https://beta.vero.site/
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