Assume that you have just heard of a scandal and you are the
first one to know. You pass it on to
four person in a matter of 30 minutes. Each of these four in
turn passes it to four other persons
in the next 30 minutes and so on.
How long it will take for everybody in the World to get to
know the scandal?
- 3 Answers
- 14621 Views
- I also Faced
- E-Mail Answers
Answers were Sorted based on User's Feedback
Answer / guest
Assume that nobody hears it more than once and the
population of the World is approximately 5.6
billions.
Everybody in the World will get to know the scandal in 8 hours.
You came to know of a scandal and you passed it on to 4
persons in 30 minutes. So total (1+4) 5
persons would know about it in 30 minutes.
By the end of one hour, 16 more persons would know about it.
So total of (1+4+16) 21 persons would
know about it in one hour.
Similarly, the other (1+4+16+64) persons would have know
about it in one and a half hours.
(1+4+16+64+256) persons would have know about it in two
hours and so on...
It can be deduced that the terms of the above series are the
power of 4 i.e. 4^0, 4^1, 4^2, 4^3 and
so on upto (2N+1) terms. Also, the last term would be 4^2N
where N is the number of hours.
Sum of the above mentioned series = [4^(2N+1)-1]/3
The sum of the series must be 5.6 billions. Hence, equating
the sum of the series with 5.6
billions, we get N=8 hours.
Scandals travel FAST !!!
| Is This Answer Correct ? | 16 Yes | 2 No |
Answer / arvind ragunathan
the sum goes out this way : 4+4^2+.....4^11 to reach 5.6
billion. the 30 minutes count starts with 5 people. so
there are 10 '30 minutes' in this sum. that amounts to 300
minutes. hence 5 hours.
| Is This Answer Correct ? | 0 Yes | 1 No |
Answer / swati
I dont know the answer, but wud like to do one small
correction in first answer posted..
in first 30 mins 4 people will come to know..
after that, for next 30 mins total 1+4 = 5 people including
urself are ready to inform another 20 people..
it's not da condition that, once u told to 4 people, u cant
continue with telling to 4 new poeople about it..
right..?! ;)
now, at da end of 1 hour total 25 people know about
scandal..
and so on........ :)
| Is This Answer Correct ? | 1 Yes | 4 No |
Replace the letters with the correct numbers. T W O X T W O --------- T H R E E
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
Dr. DoLittle always goes walking to the clinic and takes the same time while going and while coming back. One day he noticed something. When he left the home, the hour hand and the minute hand were exactly opposite to each other and when he reached the clinic, they were together. Similarly, when he left the clinic, the hour hand and the minute hand were together and when he reached the home, they were exactly opposite to each other. How much time does Dr. DoLittle take to reach home from the clinic? Give the minimal possible answer.
plz send me aptitude test questions on my email id bpraichur@gmail.com
In a group of 25, 13 can speak Latin, 15 can speak French, and 6 don’t speak either. How many of these speak both Latin and French?
There are N secret agents each know a different piece of secret information. They can telephone each other and exchange all the information they know. After the telephone call, they both know anything that either of them knew before the call. What are the minimum number of telephone calls needed so that all of the them know everything?
if u love someone u can arrange these 10 letters in 5 words I H O M U R E Y N A
41 Answers DQ Entertainment, Era Infra Engineering, Infosys,
in a family there are 5 members viz. parents and 3 children. the member are A,B,C,D AND E out of which 2 are males and 3 are females. A has 3 childerns, 2 daughters and 1 son. c in B's son. A in D's father. 1.how is E related to B? 2.who is D's mother? give me solution plese.
1 bird ko fish se pyar ho gaya. wo dono mile to kaise? fish paani ko chhod nahi sakti aur bird paani me ja nahi sakta.
3 boys ,a,b,c . have 3 chocklets .. a ate the chocklet.b thrown away the chocklet and c ate half chocklet .now how many choclect each have in their hand.
agar aapne kabhi kisi se saccha pyar kiya hai to is gaane ko complete karo K---N -O --H--T - --G--T---I-A J---N T--S-- S----H--
There are 10 statements written on a piece of paper: 1. At least one of statements 9 and 10 is true. 2. This either is the first true or the first false statement. 3. There are three consecutive statements, which are false. 4. The difference between the numbers of the last true and the first true statement divides the number, that is to be found. 5. The sum of the numbers of the true statements is the number, that is to be found. 6. This is not the last true statement. 7. The number of each true statement divides the number, that is to be found. 8. The number that is to be found is the percentage of true statements. 9. The number of divisors of the number, that is to be found, (apart from 1 and itself) is greater than the sum of the numbers of the true statements. 10. There are no three consecutive true statements. Find the minimal possible number?
English 
