Mrs. F has invited several wives of delegates to the United
Nations for an informal luncheon. She plans to seat her 9
guests ina row such that each lady will be able to converse
with the person directly to her left and right. She has
prepared the following list.
Mrs. F speaks English only.
Mrs. G speaks English and French.
Mrs. H speaks English and Russian.
Mrs. J speaks Russian only.
Mrs. K speaks English only.
Mrs. L speaks French only.
Mrs. M speaks French and German.
Mrs. N speaks English and German.
Mrs. O speaks English only.
How many distinct seating arrangements are possible? Give
all possible seating arrangements.
Note that ABCD and DCBA are the same.
Answer / guest
126 distinct seating arrangements are possible.
Mrs. J and Mrs. H must be together and Mrs. J must be at the
end as Mrs. J speaks only Russian and Mrs. H is the only
other Russian speaker.
Mrs. L speaks only French and there are two others - Mrs. G
and Mrs. M - who speak French. Here there are 2 cases.
? CASE A : Mrs. L is at the other end
If Mrs. L is at the other end, either Mrs. G or Mrs. M must
seat next to her.
o CASE AA : Mrs. G seats next to Mrs. L
Then, Mrs. M must seat next to Mrs. G and Mrs. N must seat
next to Mrs. M. This is because Mrs. M speaks French and
German, and Mrs. N is the only other German speaker. Thus,
the possible seating arrangement is JHxxxNMGL, where x is
the English speakers. Mrs. F, Mrs. K and Mrs. O can be
arranged in remaining 3 positions in 3! different ways i.e.
6 ways.
o CASE AB : Mrs. M seats next to Mrs. L
If so, then either Mrs. N or Mrs. G must seat next to Mrs. M
? CASE ABA : Mrs. N seats next to Mrs. M
Thus, the possible seating arrangement is JHxxxxNML, where x
is the English speakers. Mrs. F, Mrs. G, Mrs. K and Mrs. O
can be arranged in remaining 4 positions in 4! different
ways i.e. 24 ways.
? CASE ABB : Mrs. G seats next to Mrs. M
Thus, the possible seating arrangement is JHxxxxGML, where x
is the English speakers. Mrs. F, Mrs. K, Mrs. N and Mrs. O
can be arranged in remaining 4 positions in 4! different
ways i.e. 24 ways.
? CASE B : Mrs. L does not seat at the end
It means that Mrs. G, Mrs. L and Mrs. M must seat together.
Also, Mrs. L must seat between Mrs. G and Mrs. M.
o CASE BA : Mrs. G seats left and Mrs. M seats right to Mrs.
L i.e. GLM
? CASE BAA : GLM is at the other end
Thus, the possible seating arrangement is JHxxxxGLM, where x
is the English speakers. Mrs. F, Mrs. K, Mrs. N and Mrs. O
can be arranged in remaining 4 positions in 4! different
ways i.e. 24 ways.
? CASE BAB : GLM is not at the other end
Then Mrs. N must seat next to Mrs. M. Now, we have a group
of four GLMN where Mrs. G and Mrs. N speak English. Thus,
the possible seating arrangement is JHxxxX, where x is the
individual English speakers and X is the group of four
females with English speakers at the both ends. Thus, there
are 4! different ways i.e. 24 ways.
o CASE BB : Mrs. M seats left and Mrs. G seats right to Mrs.
L i.e. MLG
Then, Mrs. N must seat next to Mrs. M. Now, we have a group
of four NMLG where Mrs. G and Mrs. N speak English. Thus,
the possible seating arrangement is JHxxxX, where x is the
individual English speakers and X is the group of four
females with English speakers at the both ends. Thus, there
are 4! different ways i.e. 24 ways.
Thus, total different possible seating arrangements are :
= 6 (case AA) + 24 (case ABA) + 24 (case ABB) + 24 (case
BAA) + 24 (case BAB) + 24 (case BB)
= 126 seating arrangements
Thus, 126 distinct seating arrangements are poosible.
| Is This Answer Correct ? | 0 Yes | 0 No |
A person X have a certain number of mangoes, he gave 1/2 of total plus one mango to B, now he gave the 1/3 of remaining plus one mango to C, he gave the 1/4 of remaining plus one mango to D. Now he have no mango more, find how many mango was at beginning?
A number of 9 digits has the following properties: ? The number comprising the leftmost two digits is divisible by 2, that comprising the leftmost three digits is divisible by 3, the leftmost four by 4, the leftmost five by 5, and so on for the nine digits of the number i.e. the number formed from the first n digits is divisible by n, 2<=n<=9. ? Each digit in the number is different i.e. no digits are repeated. ? The digit 0 does not occur in the number i.e. it is comprised only of the digits 1-9 in some order. Find the number.
A group of friends went on a holiday to a hill station. It rained for 13 days. But when it rained in the morning, the afternoon was lovely. And when it rained in the afternoon, the day was preceded by clear morning. Altogether there were 11 very nice mornings and 12 very nice afternoons. How many days did their holiday last?
*suppose u have 2 distribute a sum rs 50 among 30 studnt .it is also decided that a male student will get double than of female student.find the no. of male n female student of class?
A polygon has 1325 diagonals. How many vertices does it have?
a is person take 10 days to do a work, b is a person take 15 days to do same work, if both do the work how many days will they take
a circle is drawn...roughly in paper...the interviewer asked me to find centre point of circle?the radius,circumference is not known?how to find it?
19 Answers Accenture, HCL, Infosys, Manhattan,
xx7 and xxx are two numbers and we have to mulitply them xx7 xxx ______ xxxx xxxxxx ______ 3xxx17 find all x's
P pages read in d mins after day p+1 pages read in d+1 mins last day 379 pages done in 317 mins find p+4
A,B,C,D are four teams.Three guys x,y,z comment about matches between four teams , X said either A or B will win Y says A will never win Z says C or B will not win only one of them is correct then who won the match.
A clock with the hours round the face in Roman block numbers, as illustrated in the sketch fell down and the dial broke into four parts....
There is a 50m long army platoon marching ahead. The last person in the platoon wants to give a letter to the first person leading the platoon. So while the platoon is marching he runs ahead, reaches the first person and hands over the letter to him and without stopping he runs and comes back to his original position. In the mean time the whole platoon has moved ahead by 50m. The question is how much distance did the last person cover in that time. Assuming that he ran the whole distance with uniform speed.