@bullseyes said:In how many ways u can write 19 as a sum of 5 odd numbers?
if only +ve & repitition is allowed
a+b+c+d+e = 19
a+b+c+d+e = 9
thus, 18c4 - 8c4 ?
a+b+c+d+e = 19
a+b+c+d+e = 9
thus, 18c4 - 8c4 ?
@bullseyes said:In how many ways u can write 19 as a sum of 5 odd numbers?
All no.s are of the form 2k+1
So,
(2a + 1) + (2b + 1) + (2c + 1) + (2d + 1) + (2e + 1) = 19
2(a + b + c + d + e) = 14
a + b + c + d + e = 7 --> C(11,4) = 330
But if we are looking for unordered sets, we would have to eliminate the repeated cases as below:
When all 5 of a,b,c,d,e are same = 0 ways
When 4 are same -> These are repeated 5 times
4x + y = 7 -> y=3,7 -> 2 ways
When 3 are same and other 2 are same => These are repeated 5!/3!2! = 10 times
3x + 2y = 7 -> y = 2 -> 1 way
When 3 are same and other 2 are distinct => These are repeated 5!/3! = 20 times
3x + y + z = 7
x = 0 -> 3 ways
x = 1 -> 1 ways
x = 2 -> 1 way
2 same, 2 same, 1 distinct => These are repeated 5!/2!2! = 30 times
2x + 2y + z = 7
x = 0 -> 3 ways
2 same, 3 distinct => These are repeated 60 times
2x + y + z + t = 7
x = 0 -> 1 way
x = 1 -> 1 way
Total unordered sets = 2 + 1 + 5 + 3 + 2 = 13
So 13 ways to achieve this.
2 women Katrina and Deepika are working on an embroidery design. If Deepika worked alone, she would need 8 hours more to complete the design than if they both worked together. Now, if Katrina worked alone, she would need 4.5 hours more to complete the design than if they were working together. What time would it take for Katrina alone to complete the design?
1) 10.5 hours
2) 12.5 hours
3) 14.5 hours
4) 18.5 hours
@soumitrabengeri said:2 women Katrina and Deepika are working on an embroidery design. If Deepika worked alone, she would need 8 hours more to complete the design than if they both worked together. Now, if Katrina worked alone, she would need 4.5 hours more to complete the design than if they were working together. What time would it take for Katrina alone to complete the design?1) 10.5 hours2) 12.5 hours3) 14.5 hours4) 18.5 hours
time taken by both katrina and deepika together = rt( 8 *4.5) = rt(36) = 6
so time taken by katrina = 6 + 4.5 = 10.5 hrs
@soumitrabengeri said:2 women Katrina and Deepika are working on an embroidery design. If Deepika worked alone, she would need 8 hours more to complete the design than if they both worked together. Now, if Katrina worked alone, she would need 4.5 hours more to complete the design than if they were working together. What time would it take for Katrina alone to complete the design?1) 10.5 hours2) 12.5 hours3) 14.5 hours4) 18.5 hours
1/K + 1/D = 1/x
1/D = 1/(x+8)
1/K = 1/(x + 4.5)
x = 6
K = x + 4.5
= 10.5
1/D = 1/(x+8)
1/K = 1/(x + 4.5)
x = 6
K = x + 4.5
= 10.5
@soumitrabengeri said:2 women Katrina and Deepika are working on an embroidery design. If Deepika worked alone, she would need 8 hours more to complete the design than if they both worked together. Now, if Katrina worked alone, she would need 4.5 hours more to complete the design than if they were working together. What time would it take for Katrina alone to complete the design?1) 10.5 hours2) 12.5 hours3) 14.5 hours4) 18.5 hours
10.5 hrs 
@rkshtsurana said:time taken by both katrina and deepika together = rt( 8 *4.5) = rt(36) = 6so time taken by katrina = 6 + 4.5 = 10.5 hrs
Bhai, yeh kuansa formula hai? 
Generalised form btana :)
Amit, Sumit and Pramit go to a seaside town to spend a vacation there and on the first day everybody decides to visit different tourist locations. After breakfast, each of them boards a different tourist vehicle from the nearest bus-depot. After three hours, Sumit who had gone to a famous sea - beach, calls on the mobile of Pramit and claims that he has observed a shark in the waters. Pramit learns from the local guide that at that time of the year, only eight sea - creatures (including a shark) are observable and the probability of observing any creature is equal. However, Amit and Pramit later recall during their discussion that Sumit has a reputation for not telling the truth five out of six times. What is the probability that Sumit actually observed a shark in the waters?
1/36 , 1/30 , 5/36 , 1/24
@choosen04 said:Bhai, yeh kuansa formula hai? Generalised form btana
if A takes a hrs more than time taken by both A and B together , and B takes b hrs more than time taken by both A and B together, then the time taken by A and B together is root(a*b)
@ani4588 said:Amit, Sumit and Pramit go to a seaside town to spend a vacation there and on the first day everybody decides to visit different tourist locations. After breakfast, each of them boards a different tourist vehicle from the nearest bus-depot. After three hours, Sumit who had gone to a famous sea - beach, calls on the mobile of Pramit and claims that he has observed a shark in the waters. Pramit learns from the local guide that at that time of the year, only eight sea - creatures (including a shark) are observable and the probability of observing any creature is equal. However, Amit and Pramit later recall during their discussion that Sumit has a reputation for not telling the truth five out of six times. What is the probability that Sumit actually observed a shark in the waters?1/36 , 1/30 , 5/36 , 1/24
Good question..
The answer should be 1/36
(1/48) / (1/48+35/48)
Please correct me if i am wrong
@ani4588 said:Amit, Sumit and Pramit go to a seaside town to spend a vacation there and on the first day everybody decides to visit different tourist locations. After breakfast, each of them boards a different tourist vehicle from the nearest bus-depot. After three hours, Sumit who had gone to a famous sea - beach, calls on the mobile of Pramit and claims that he has observed a shark in the waters. Pramit learns from the local guide that at that time of the year, only eight sea - creatures (including a shark) are observable and the probability of observing any creature is equal. However, Amit and Pramit later recall during their discussion that Sumit has a reputation for not telling the truth five out of six times. What is the probability that Sumit actually observed a shark in the waters?1/36 , 1/30 , 5/36 , 1/24
1/36?
probability of him lying = 7/8 * 5/6 = 35/48
probability of him telling the truth = 1/8 * 1/6 = 1/48
It is given that he said he observed a shark.
Probability of him telling the truth with the given condition = 1/48 / (35/48 + 1/48)
= 1/36
probability of him lying = 7/8 * 5/6 = 35/48
probability of him telling the truth = 1/8 * 1/6 = 1/48
It is given that he said he observed a shark.
Probability of him telling the truth with the given condition = 1/48 / (35/48 + 1/48)
= 1/36
@rkshtsurana : Does this formula hold true for every case....?
I mean, if we take a case of let say, three persons and one person is taking 6 hours more than the all three working together, second person takes 3 horse more than all three working together, and third takes 12 hours more than all three working together.
What would be the answer of time taken by all three working together in this case?
In how many ways can the letters of the English alphabet be arranged so that there are 7 letters between the letters A and B?
1) 31!*2!
2) 24P7*18!*2
3) 36*24!
4) 26P7*20!*2
@vijay_chandola said:@rkshtsurana : Does this formula true for every case....?I mean, if we take a case of let say, three persons and one person is taking 6 hours more than the all three working together, second person takes 3 horse more than all three working together, and third takes 12 hours more than all three working together.What would be the answer of time taken by all three working together in this case?
its valid for 2 person....time k solution me dekha tha...3 wale set ka dekha nhi
@soumitrabengeri said:In how many ways can the letters of the English alphabet be arranged so that there are 7 letters between the letters A and B?1) 31!*2!2) 24P7*18!*23) 36*24!4) 26P7*20!*2
2 OPTION..
A and B ko arrange krne k 2 ways
24 me se 7 select kro and arrange kro 24P7
thn Aand b and yeh & alphabet ka 1 gropu bana lo and rest 17 k sath arrnage kro 18!
A and B ko arrange krne k 2 ways
24 me se 7 select kro and arrange kro 24P7
thn Aand b and yeh & alphabet ka 1 gropu bana lo and rest 17 k sath arrnage kro 18!
@soumitrabengeri said:In how many ways can the letters of the English alphabet be arranged so that there are 7 letters between the letters A and B?1) 31!*2!2) 24P7*18!*23) 36*24!4) 26P7*20!*2
Arrange A and B by 2!
permutation of 7 letters between A and B=P(24, 7)
rest letters+1(AxxxxxxxB) can be arranged by (26-7-2+1)!=18!
==> A total number of 2!*P(24, 7)*18! option 2)
Golu's family consists of 12 persons, each having a different age. Golu is the second youngest family member. The youngest member weighs 22 kg and is also the lightest in weight. Also the eldest member's weight is 102 kg. From the third youngest member onwards, every member's weight is average of weights of all the members younger to him. What is Golu's weight?Choose one answer.
a. 162 kgb. 102 kgc. 92 kgd. 62 kge. 182 kg
@rkshtsurana said:2 OPTION..A and B ko arrange krne k 2 ways24 me se 7 select kro and arrange kro 24P7thn Aand b and yeh & alphabet ka 1 gropu bana lo and rest 17 k sath arrnage kro 18!
@vijay_chandola said:Arrange A and B by 2!permutation of 7 letters between A and B=P(24, 7)rest letters+1(AxxxxxxxB) can be arranged by (26-7-2+1)!=18!==> A total number of 2!*P(24, 7)*18! option 2)
Seems to be correct and even i got the same answer but the OA has been given as (c)
The explanation is given as follows..question is from Arun Sharma
A and B can occupy 1st and 9th places..2nd and 10th...3rd and 11th places and so on..
This can be done in 18 ways
A and B can be arranged in 2 ways
All the other 24 alphabets can be arranged in 24! ways..how is this possible?
Hence their answer comes out to be 2*18*24! = 36*24!
Option (c)