ginally Posted by Arjun verma View Post
how many words are possible from the letters of the word PERMUTATION?
a. 11!/2!
b. (11!/2!)-1
c. 11!-1
(please do explain the approach)
but in arun sharma, B as an answer is mentioned
A class prefect goes to meet the principal every week. his class has 30 people besides him. if he has to take groups of three every time he goes to the principal, in how many weeks will he be able to go to the principal without repeating the group of same three which accompanies him?
a. 30P3
b. 30C3
c.30!/3
d. none of these
(please explain the approach too)
Thanks Swaminathan, and wonderfull explaination too. please help me with the other question and the following question.
There are 5 blue socks, 4 red socks and 3 green socks in Debu's wardrobe. He has to select 4 socks from this set. In how many ways can he do so?
A. 245
B. 120
C. 495
D. 60
total no. of socks=5+4+3=12.
u select 4 out of 12.
so answer=12C4=495.
Arjun, in pg u need'nt thank explicitly. Pressing the sweet little thank button would do.
.
ginally Posted by Arjun verma View Post
how many words are possible from the letters of the word PERMUTATION?
a. 11!/2!
b. (11!/2!)-1
c. 11!-1
(please do explain the approach)
but in arun sharma, B as an answer is mentioned
This will be the answer for the question where all possible words are considered, except one word (may be the word "permutation" , as the case may be).
here u consider all possibilities and subtract the unwanted one.
A class prefect goes to meet the principal every week. his class has 30 people besides him. if he has to take groups of three every time he goes to the principal, in how many weeks will he be able to go to the principal without repeating the group of same three which accompanies him?
a. 30P3
b. 30C3
c.30!/3
d. none of these
(please explain the approach too)
I assume that he takes 3 ppl excluding him.(3+1)
so from 30 ppl u select 3 each time.
so total combinations (total selections)=30c3.
Now each 3 member team can be arranged in 3! ways.
so 30C3*3!=30P3 which is the req. answer.
but answer is 30C3, in arun sharma,
how many 4 digit number divisible by 5 can be formed with the digits 0,1,2,3,4,5,6 and 6.
a. 220
b. 588
c. 432
d. 216
Originally Posted by Arjun verma View Post
Thanks Swaminathan, and wonderfull explaination too. please help me with the other question and the following question.
There are 5 blue socks, 4 red socks and 3 green socks in Debu's wardrobe. He has to select 4 socks from this set. In how many ways can he do so?
A. 245
B. 120
C. 495
D. 60
total no. of socks=5+4+3=12.
u select 4 out of 12.
so answer=12C4=495.
Arjun, in pg u need'nt thank explicitly. Pressing the sweet little thank button would do.
.
so that means, the color of the socks doesnot make any impact on the question?
Arjun verma Saysbut answer is 30C3, in arun sharma,
Sorry...made a mistake.
answer is 30c3.
say first i take a group of 3(a,b,c).
now whether i take it in that order or any other order will be the same.
ie (a,b,c) ,(a,c,b), (b,c,a),(b,a,c), (c,a,b) and(c,b,a) will be the same.
since here i am not bothered about the arrangement.
all i am bothered is first week i take (a,b,c)
next week i take (b,c,d) or any other pattern.
mistake regretted!!!
please help me with the following question
In how many ways 5 CA students and 6 law students can be arranged together so that no two CA students are side by side?
(a) 7!6!/2! (b) 6!*6! (c) 5!6! (d) 11P5.
i am getting 6!*7P5, as the answer. please do post your appproach
please help me with the following question
the latest registration number issued by the Delhi Motor Vehicle Registration Authority is DL-5S2234.If all the numbers and alphabets before this have been used up then find how many vehicles have a registration number starting with DL-5?
A>1,92,234 B>1,92,225
C>1,72,227 D>1,82,216
please do post your approach too
please help me with the following question
the number of positive numbers of not more than 10 digits formed using 0,1,2,3 is
a. 4^10 - 1
b. 4^10
c. 4^9 - 1
d. 4^9
please do post your approach, answer mentioned is (a)
it might be A. 220
please help me with the following question
In how many ways 5 CA students and 6 law students can be arranged together so that no two CA students are side by side?
(a) 7!6!/2! (b) 6!*6! (c) 5!6! (d) 11P5.
i am getting 6!*7P5, as the answer. please do post your appproach
arranging 6 law students can be done in 6! ways whereas 5CA student can be arranged in 7 places left between 6 law studs, this can be done in 7C5 * 5! ways.( first selecting 5 places from 7 then arranging 5CA studs in that places)......
please help me with the following question
the latest registration number issued by the Delhi Motor Vehicle Registration Authority is DL-5S2234.If all the numbers and alphabets before this have been used up then find how many vehicles have a registration number starting with DL-5?
A>1,92,234 B>1,92,225
C>1,72,227 D>1,82,216
please do post your approach too
my take on D(182216)
my take on D(182216)
please help me with the following question
the latest registration number issued by the Delhi Motor Vehicle Registration Authority is DL-5S2234.If all the numbers and alphabets before this have been used up then find how many vehicles have a registration number starting with DL-5?
A>1,92,234 B>1,92,225
C>1,72,227 D>1,82,216
please do post your approach too
my take on D(182216)
please help me with the following question
the number of positive numbers of not more than 10 digits formed using 0,1,2,3 is
a. 4^10 - 1
b. 4^10
c. 4^9 - 1
d. 4^9
please do post your approach, answer mentioned is (a)
0,1,2,3
consider 10 places _ _ _ _ _ _ _ _ _ _
nos. eligible for 1st places are 0,1,2,3 (if 0 then number will become a 9 digits number which is perfectly acceptable acc. to the ques.)
similarly for other places also...
so number of ways are 4^10
but as we only require positive numbers so '0' cannot be included in this , therefore answer will be 4^10-1
hope it helps.
please help me with the following question
the number of positive numbers of not more than 10 digits formed using 0,1,2,3 is
a. 4^10 - 1
b. 4^10
c. 4^9 - 1
d. 4^9
please do post your approach, answer mentioned is (a)
Imagine the ten digits as ten boxes to be filled with the given four digits!
So , first box can be filled in 4 ways i.e 0 or 1 or 2 or 3.
Similarly other nine boxes can be filled in 4 ways respectively.
So this gives us : 4x4x4x4x4x4x4x4x4x4 i.e 4 ^10.
But we have put 0 as this is not positive number.
Hence we will subtract 1.
This will Give our answer as :4^10-1 .
Hope I am correct in my approach 😃
Originally Posted by Arjun verma View Post
Thanks Swaminathan, and wonderfull explaination too. please help me with the other question and the following question.
There are 5 blue socks, 4 red socks and 3 green socks in Debu's wardrobe. He has to select 4 socks from this set. In how many ways can he do so?
A. 245
B. 120
C. 495
D. 60
total no. of socks=5+4+3=12.
u select 4 out of 12.
so answer=12C4=495.
Arjun, in pg u need'nt thank explicitly. Pressing the sweet little thank button would do.
so that means, the color of the socks doesnot make any impact on the question?
Here nothin abt. the "pair" is specified.