Questions on Algebra: Combinatorics and Permutations answered by real tutors!

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Question 1085188: Please Tutor help me solve this question. Find n if p(n,4) = 42 p(n,1)
Click here to see answer by ikleyn(52780) About Me 

Question 1085186: Please Tutor help me with Question. Find n if p(n,4) = 42 (p(n,1)
Click here to see answer by ikleyn(52780) About Me 

Question 1085119: If repetition is not allowed,how many 4 digit numbers can be formed with the integers 0,1,3,4,5,6,7,8,9? How many of these are between 2000 and 8000?
Click here to see answer by Alan3354(69443) About Me 

Question 1085209: IF 10% OF A POPULATION OF PARTS IS DEFECTIVE, WHAT IS THE PROBABILITY OF RANDOMLY SELECTING 80 PARTS AND FINDING THAT 12 OR MORE ARE DEFECTIVE?
Click here to see answer by stanbon(75887) About Me 

Question 1085211: A NORMAL POPULATION HAS STANDARD DEVIATION OF 10. A RANDOM SAMPLE OF SIZE 25 HAS A MEAN OF 50. CONSTRUCT A 95% CONFIDENCE INTERVAL ESTMATE OF THE POPULATION MEAN.
Click here to see answer by stanbon(75887) About Me 

Question 1085208: SUPPOSE THAT DURING ANY HOUR IN A LARGE DEPARTMENT STORE, THE AVERAGE NUMBER OF SHOPPERS IS 448 , WITH A STANDARD DEVIATION OF 21 SHOPPERS. WHAT IS THE PROBABILITY OF RANDOMLY SELECTING 49 DIFFERENT SHOPPING HOURS, COUNTING THE SHOPPERS, AND HAVING THE SAMPLE MEAN FALL BETWEEN 441 AND 446 SHOPPERS, INCLUSIVE ?
Click here to see answer by stanbon(75887) About Me 

Question 1085207: A RANDOM SAMPLE OF 400 MEMBERS OF LABOR FORCE IN A FIVE STATE REGION SHOWED THAT 32 WERE UNEMPLOYED. CONSTRUCT THE 95% CONFIDENCE INTERVAL FOR THE PROPORTION UNEMPLOYED IN THE REGION.
Click here to see answer by Boreal(15235) About Me 

Question 1085206: THE ENVIRONMENTAL PROTECTION OFFICER OF A LARGE INDUSTRIAL PLANT SOUGHT TO DETERMINE THE MEAN DAILY AMOUNT OF SULPHUR OXIDE (POLLUTANT)EMMITED BY THE PLANT. BECAUSE MEASURMENTS COSTS WERE HIGH, ONLY A RANDOM SAMPLE 10 DAYS MEASURMENTS WERE OBTAINED : THESE WERE , IN TONS PER DAY.
8 7 10 15 11 5 8 5 13 12
SUPPOSE EMISSIONS PER DAY ARE NORMALLY DISTRIBUTED. ESTIMATED µ, THE MEAN AMOUNT OF SULPHUR OXIDES EMITTED PER DAY USING THE CONFIDENCE INTERVAL WITH A CONFIDENCE
COEFFICIENT OF 0.95

Click here to see answer by Boreal(15235) About Me 

Question 1085205: A NORMAL POPULATION HAS STANDARD DEVIATION OF 10. A RANDOM SAMPLE OF SIZE 25 HAS A MEAN OF 50. CONSTRUCT A 95% CONFIDENCE INTERVAL ESTMATE OF THE POPULATION MEAN.
Click here to see answer by Boreal(15235) About Me 

Question 1084962: Q1)A NORMAL POPULATION HAS STANDARD DEVIATION OF 10. A RANDOM SAMPLE OF SIZE 25 HAS A MEAN OF 50. CONSTRUCT A 95% CONFIDENCE INTERVAL ESTMATE OF THE POPULATION MEAN.
Q2)THE ENVIRONMENTAL PROTECTION OFFICER OF A LARGE INDUSTRIAL PLANT SOUGHT TO DETERMINE THE MEAN DAILY AMOUNT OF SULPHUR OXIDE (POLLUTANT)EMMITED BY THE PLANT. BECAUSE MEASURMENTS COSTS WERE HIGH, ONLY A RANDOM SAMPLE 10 DAYS MEASURMENTS WERE OBTAINED : THESE WERE , IN TONS PER DAY.
8 7 10 15 11 5 8 5 13 12
SUPPOSE EMISSIONS PER DAY ARE NORMALLY DISTRIBUTED. ESTIMATED µ, THE MEAN AMOUNT OF SULPHUR OXIDES EMITTED PER DAY USING THE CONFIDENCE INTERVAL WITH A CONFIDENCE
COEFFICIENT OF 0.95
Q3)A RANDOM SAMPLE OF 400 MEMBERS OF LABOUR FORCE IN A FIVE STATE REGION SHOWED THAT 32 WERE UNEMPLOYED. CONSTRCT THE 95% CONFIDENCE INTERVAL FOR THE PROPORTION UNEMPLOYED IN THE REGION.
Q4)SUPPOSE THAT DURING ANY HOUR IN A LARGE DEPARTMENT STORE, THE AVERAGE NUMBER OF SHOPPERS IS 448 , WITH A STANDARD DEVIATION OF 21 SHOPPERS. WHAT IS THE PROBABILITY OF RANDOMLY SELECTING 49 DIFFERENT SHOPPING HOURS, COUNTING THE SHOPPERS, AND HAVING THE SAMPLE MEAN FALL BETWEEN 441 AND 446 SHOPPERS, INCLUSIVE/
zQ5)IF 10% OF A POPULATION OF PARTS IS DEFECTIVE, WHAT IS THE PROBABILITY OF RANDOMLY SELECTING 80 PARTS AND FINDING THAT 12 OR MORE ARE DEFECTIVE?
Q6)SUPPOSE THAT A POPULATIN PROPORTION IS , 40 AND THAT 80% OF THE TIME YOU DRAW A RANDOM SAMPLE FROM THIS POPULATION , YOU GET A SAMPLE PROPORTION OF 0.35 OR MORE. HOW LARGE A SAMPLE WERE YOU TAKING?
Q7)ASSUME THAT THE LENGTH OF TIME . X. BETWEEN CHARGES OF A CELLULAR PHONE IS NORMALLY DISTIBUTED WITH A MEAN OF 10 HOURS AND A STANDARD DEVIATON OF 1.5 HOURS. FIND THE PROBABILITY THAT THE CELL PHONE WILL LAST BETWEEN 8 AND 12 HOURS BETWEEN CHARGES.
Q8)SUPPOSE AN AUTOMOBILE MANUFACTURER INTRODUCES A NEW MODEL THAT HAS AN ADVERTISED MEAN IN CITY MILEAGE OF 27 MILES PER GALLON. ALTHOUGH SUCH ADVERTISEMENT SELDOM REPORT ANY MEASURE OF VARIABLILITY . SUPPOSE YOU WRITE THE MANUFACTURER FOR THE DETAILS OF THE TESTS, AND YOU FIND THAT THE STANDARD DEVIATION IS 3 MILES PER GALLON. THIS INFORMANTION LEADS YOU TO FORMULATE A PROBABILITY MODEL FOR THE RANDOM VARIABLE X , THE IN-CIY MILEAGE FOR THIS CAR MODEL . YOU BELIEVE THAT THE PROBABILITY DISTRIBUTION OF X CAN BE APPROXIMATED BY A NORMAL DISTRIBUTION WITH A MEAN OF 27 AND A STANDARD DEVIATION OF 3.
IF YOU WERE TO BUY THIS MODEL OF AUTOMOBILE, WHAT IS THE PROBABILITY THAT YOU WOULD PURCHASEDONE THAT AVERAGES LESS THAN 20 MILES PER GALLON FOR IN-CITY DRIVING? IN OTHER WORDS, FIND P(X<20).
SUPPOSE YOU PURCHASE ONE OF THESE NEW MODELS AND IT DOES GET LESS THAN 20 MILES PER GALLON FOR IN-CITY DRIVING. SHOULD YOU CONCLUDE THAT YOUR PROBABILITY MODEL IS INCORRECT?

Click here to see answer by ikleyn(52780) About Me 

Question 1085261: 2 bananas are to be selected from a group of 8. In how many ways can this be done?
Click here to see answer by jim_thompson5910(35256) About Me 

Question 1085260: 4 Students volunteer for a committee. How many different 2-person committees can be chosen?
Click here to see answer by Boreal(15235) About Me 

Question 1085258: You own 10 hats and are taking 3 on vacation. In how many ways can you choose 3 hats from the 10?
Click here to see answer by Boreal(15235) About Me 

Question 1085298: SUPPOSE AN AUTOMOBILE MANUFACTURER INTRODUCES A NEW MODEL THAT HAS AN ADVERTISED MEAN IN CITY MILEAGE OF 27 MILES PER GALLON. ALTHOUGH SUCH ADVERTISEMENT SELDOM REPORT ANY MEASURE OF VARIABLILITY . SUPPOSE YOU WRITE THE MANUFACTURER FOR THE DETAILS OF THE TESTS, AND YOU FIND THAT THE STANDARD DEVIATION IS 3 MILES PER GALLON. THIS INFORMANTION LEADS YOU TO FORMULATE A PROBABILITY MODEL FOR THE RANDOM VARIABLE X , THE IN-CIY MILEAGE FOR THIS CAR MODEL . YOU BELIEVE THAT THE PROBABILITY DISTRIBUTION OF X CAN BE APPROXIMATED BY A NORMAL DISTRIBUTION WITH A MEAN OF 27 AND A STANDARD DEVIATION OF 3.
IF YOU WERE TO BUY THIS MODEL OF AUTOMOBILE, WHAT IS THE PROBABILITY THAT YOU WOULD PURCHASEDONE THAT AVERAGES LESS THAN 20 MILES PER GALLON FOR IN-CITY DRIVING? IN OTHER WORDS, FIND P(X<20).
SUPPOSE YOU PURCHASE ONE OF THESE NEW MODELS AND IT DOES GET LESS THAN 20 MILES PER GALLON FOR IN-CITY DRIVING. SHOULD YOU CONCLUDE THAT YOUR PROBABILITY MODEL IS INCORRECT?

Click here to see answer by user_dude2008(1862) About Me 

Question 1085297: ASSUME THAT THE LENGTH OF TIME . X. BETWEEN CHARGES OF A CELLULAR PHONE IS NORMALLY DISTIBUTED WITH A MEAN OF 10 HOURS AND A STANDARD DEVIATON OF 1.5 HOURS. FIND THE PROBABILITY THAT THE CELL PHONE WILL LAST BETWEEN 8 AND 12 HOURS BETWEEN CHARGES.
Click here to see answer by Boreal(15235) About Me 

Question 1085299: SUPPOSE THAT A POPULATION PROPORTION IS . 40 AND THAT 80% OF THE TIME YOU DRAW A RANDOM SAMPLE FROM THIS POPULATION , YOU GET A SAMPLE PROPORTION OF 0.35 OR MORE. HOW LARGE A SAMPLE WERE YOU TAKING?
Click here to see answer by Theo(13342) About Me 

Question 1085739: In a special movie club, you have a choice of watching any 3 movies out of 45 possibilities each month. How many different ways can you choose the 3 movies?

Click here to see answer by addingup(3677) About Me 

Question 1085775: Hi, I just want to clarify something:
Is there a rule for factorials that is a!-(b!c!) = ac!-bc! ?
An example is 8! - (7!2!), which apparently simplifies to 8*7! - 2*7! = 6*7! = 30240
Could you please explain how this 'formula' works?
Thank you very much

Click here to see answer by math_helper(2461) About Me 
Question 1085775: Hi, I just want to clarify something:
Is there a rule for factorials that is a!-(b!c!) = ac!-bc! ?
An example is 8! - (7!2!), which apparently simplifies to 8*7! - 2*7! = 6*7! = 30240
Could you please explain how this 'formula' works?
Thank you very much

Click here to see answer by natolino_2017(77) About Me 
Question 1085775: Hi, I just want to clarify something:
Is there a rule for factorials that is a!-(b!c!) = ac!-bc! ?
An example is 8! - (7!2!), which apparently simplifies to 8*7! - 2*7! = 6*7! = 30240
Could you please explain how this 'formula' works?
Thank you very much

Click here to see answer by MathTherapy(10552) About Me 

Question 1084726: ACCORDING TO A STUDY CONDUCTED
APPROXIMATELY 55% OF ALL HOSPITALS
IN A
GIVEN TOWN CONTAINED 100 OR MORE
BEDS. A RESEARCHER DRAWS A SAMPLE
OF 15
HOSPITALS BY RANDOMLY SELECTING
NAMES FROM A DIRECTORY OF HOSPITALS.
A/ WHAT IS THE PROBABILITY OF
SELECTING 10 OR MORE HOSPITALS THAT
HAVE 100
OR MORE BEDS?
B/ WHAT IS THE PROBABILITY FO
SELECTING LESS THAN FIVE HOSPITALS
THAT HAVE
100 OR MORE BEDS?
C/ WHAT IS THE PROBABILITY OF
SELECTING FROM SIX TO TEN HOSPITALS,
INCLUSICE, THAT HAVE 100 OR MORE
BEDS?

Click here to see answer by mathmate(429) About Me 

Question 1084486: How many different meals are possible? Astronauts each consume 3000 calories a day. One meal consist of a main dish a vegetable dish and two different desserts. The astronauts can choose from 10 main dishes 8 vegetables dishes and 15 desserts. How many different meals are possible?
Click here to see answer by mathmate(429) About Me 

Question 1085855: In how many ways can 5 workers be appointed to different posts?
Click here to see answer by mathmate(429) About Me 

Question 1085902: Dear Tutor,
please help me.
20 students take a test with three questions A,B and C. 16 students answer at least one question correctly. 10 answer question A correctly, 8 answer question B correctly, 6 answer question C correctly. 3 students answer both A and B correctly, 4 answer A and C correctly and 1 student answers all three questions correctly. How many students answer questions B and C correctly?
Could you please explain steps taken while solving this problem?
Thank you.

Click here to see answer by Theo(13342) About Me 
Question 1085902: Dear Tutor,
please help me.
20 students take a test with three questions A,B and C. 16 students answer at least one question correctly. 10 answer question A correctly, 8 answer question B correctly, 6 answer question C correctly. 3 students answer both A and B correctly, 4 answer A and C correctly and 1 student answers all three questions correctly. How many students answer questions B and C correctly?
Could you please explain steps taken while solving this problem?
Thank you.

Click here to see answer by ikleyn(52780) About Me 

Question 1085955: what is the solution to
6 freshmen, 7 sophomores, 7 juniors, and 7 seniors are eligible to be on a committee.
In how many ways can a dance committee of 10 students be chosen if it is to consist of exactly 3 juniors and exactly 2 seniors, and the rest must be freshman or sophomores?

Click here to see answer by Boreal(15235) About Me 

Question 1086262: how many no. lying between 10 and 1000 can be formed from the digits 1,2,3,4,5,6,7,8,9
Click here to see answer by josmiceli(19441) About Me 

Question 1086412: A committee of 6 persons to be formed from 4 men and 6 women.In how many ways can this be done when atmost 3 women are included?
Click here to see answer by math_helper(2461) About Me 

Question 1086846: if 3 books are picked at random from a shelf containing 5 novel, 3 books of poems, and a dictionary, in how many ways this can be don't if there is no restriction, the dictionary is selected and 2 novels and 1 book of poems are selected?
Click here to see answer by Boreal(15235) About Me 

Question 1086887: 6 letter codes are formed by using the letters from the word EDUCATION without any repeitition. Find the number of different codes that begin with a consonant and end with a vowel
Click here to see answer by Edwin McCravy(20054) About Me 

Question 1087253: In a student union meeting in a school, 16 students show up.Each shakes hands with each other exactly once.Determine the total number of handshakes.


Click here to see answer by jim_thompson5910(35256) About Me 

Question 1087409: Stats problem In how many ways can 15 students be lined up?
Click here to see answer by jim_thompson5910(35256) About Me 

Question 1087410: Stats problem In the U.S. Senate, there are 1 members on the Committee on Banking,Housing, and Urban Affairs. Nine of the 21 members are selected to be on the Subcommittee on Economic Policy. How many different committee structures are possible for this subcommittee?
Click here to see answer by jorel1380(3719) About Me 

Question 1087408: Stats question: An IRS inspector is to select 3 corporations from a list of 15 for tax audit purposes. Of the 15 corporations, 6 earned profits and 9 incurred losses during the year for which the tax returns are to be audited. If the IRS inspector decide to select 3 corporations randomly, find the probability (using the Hypergeometric formula) that the number of corporations in these 3 that incurred losses during the year for which the tax returns are to be audited is
Click here to see answer by rothauserc(4718) About Me 

Question 1087549: in how many ways can 5 people seated in a car with 5 seats when 3 of them can drive.
Click here to see answer by mathmate(429) About Me 

Question 1087647: if a fair dice is tossed one (find the probability of getting (a) 4 (b) 6.?

Click here to see answer by Fombitz(32388) About Me 

Question 1087968: Perform the indicated integral.
i. ∫ x^2e^xdx
ii. ∫ x ln(x)dx

Click here to see answer by Edwin McCravy(20054) About Me 

Question 1087967: (i)Determine in how many ways can 4 boys and 2 girls be seated in a row when the
boys and girls can sit anywhere?
(ii)When the 2 girls must be together and
(iii) When the 2 girls must be separated?

Click here to see answer by mathmate(429) About Me 

Question 1088064: Five identical green flags,4 identical red flags and 3 identical yellow flags are to be hanged on a row of 12 poles.In how many ways can those flags be arranged?
Click here to see answer by Tatiana_Stebko(1539) About Me 

Question 1088065: Three presidents,3 secretaries and 3 treasurer's are to occupy 9 seats for a round table discussion about a certain issue.In how many ways can they arranged themselves if
1.they sit anywhere they want
2.Presidents sit together?
3.Secretaries sit together and treasurer's sit together?

Click here to see answer by Edwin McCravy(20054) About Me 

Question 1088066: From a group of 10 members of a board ,how many committees of 5 members can form?

Click here to see answer by Edwin McCravy(20054) About Me 

Question 1088174: A group of 8 ladies would like to arrange themselves for picture taking.In how many ways can they arranged themselves in a row if 1.no one is excluded
2.)only 5 can join in every pose

Click here to see answer by ikleyn(52780) About Me 

Question 1088175: In a box, there are 3 red marbles,4 green marbles and 5 yellow marbles.In how many ways can you draw three marbles if
1). they are of the same color?
2)they are of 3 different colors?

Click here to see answer by jim_thompson5910(35256) About Me 

Question 1088244: algebra
Click here to see answer by ikleyn(52780) About Me 

Question 1088292: From the letters of the word HONESTY, how many 3 letter words
can be formed if repetition is 1 Allowed? 2 not allowed?

Click here to see answer by Edwin McCravy(20054) About Me 

Older solutions: 1..45, 46..90, 91..135, 136..180, 181..225, 226..270, 271..315, 316..360, 361..405, 406..450, 451..495, 496..540, 541..585, 586..630, 631..675, 676..720, 721..765, 766..810, 811..855, 856..900, 901..945, 946..990, 991..1035, 1036..1080, 1081..1125, 1126..1170, 1171..1215, 1216..1260, 1261..1305, 1306..1350, 1351..1395, 1396..1440, 1441..1485, 1486..1530, 1531..1575, 1576..1620, 1621..1665, 1666..1710, 1711..1755, 1756..1800, 1801..1845, 1846..1890, 1891..1935, 1936..1980, 1981..2025, 2026..2070, 2071..2115, 2116..2160, 2161..2205, 2206..2250, 2251..2295, 2296..2340, 2341..2385, 2386..2430, 2431..2475, 2476..2520, 2521..2565, 2566..2610, 2611..2655, 2656..2700, 2701..2745, 2746..2790, 2791..2835, 2836..2880, 2881..2925, 2926..2970, 2971..3015, 3016..3060, 3061..3105, 3106..3150, 3151..3195, 3196..3240, 3241..3285, 3286..3330, 3331..3375, 3376..3420, 3421..3465, 3466..3510, 3511..3555, 3556..3600, 3601..3645, 3646..3690, 3691..3735, 3736..3780, 3781..3825, 3826..3870, 3871..3915, 3916..3960, 3961..4005, 4006..4050, 4051..4095, 4096..4140, 4141..4185, 4186..4230, 4231..4275, 4276..4320, 4321..4365, 4366..4410, 4411..4455, 4456..4500, 4501..4545, 4546..4590, 4591..4635, 4636..4680, 4681..4725, 4726..4770, 4771..4815, 4816..4860, 4861..4905, 4906..4950, 4951..4995, 4996..5040, 5041..5085, 5086..5130, 5131..5175, 5176..5220, 5221..5265, 5266..5310, 5311..5355, 5356..5400, 5401..5445, 5446..5490, 5491..5535, 5536..5580, 5581..5625, 5626..5670, 5671..5715, 5716..5760, 5761..5805, 5806..5850, 5851..5895, 5896..5940, 5941..5985, 5986..6030, 6031..6075, 6076..6120, 6121..6165, 6166..6210, 6211..6255, 6256..6300, 6301..6345, 6346..6390, 6391..6435, 6436..6480, 6481..6525, 6526..6570, 6571..6615, 6616..6660, 6661..6705, 6706..6750, 6751..6795, 6796..6840, 6841..6885, 6886..6930, 6931..6975, 6976..7020, 7021..7065, 7066..7110, 7111..7155, 7156..7200, 7201..7245, 7246..7290, 7291..7335, 7336..7380, 7381..7425, 7426..7470, 7471..7515, 7516..7560, 7561..7605, 7606..7650, 7651..7695, 7696..7740, 7741..7785, 7786..7830, 7831..7875, 7876..7920, 7921..7965, 7966..8010, 8011..8055, 8056..8100, 8101..8145, 8146..8190, 8191..8235, 8236..8280, 8281..8325, 8326..8370, 8371..8415, 8416..8460, 8461..8505, 8506..8550, 8551..8595, 8596..8640, 8641..8685, 8686..8730, 8731..8775, 8776..8820, 8821..8865, 8866..8910, 8911..8955, 8956..9000, 9001..9045, 9046..9090, 9091..9135, 9136..9180, 9181..9225, 9226..9270, 9271..9315, 9316..9360, 9361..9405, 9406..9450, 9451..9495, 9496..9540, 9541..9585, 9586..9630, 9631..9675, 9676..9720, 9721..9765, 9766..9810, 9811..9855, 9856..9900, 9901..9945, 9946..9990, 9991..10035