25. It takes five minutes to pass a rumour from one
person to two other persons. The tree of rumour continues.
Find how many minutes does it take spread the rumour to 768
persons. ?
Answers were Sorted based on User's Feedback
Answer / pradeep
Yes Bindu, You are right and thanks for correcting me.
and the right answer is 35 minutes.
Please find the logic and the program below:
int ppl , time , i , sum = 0;
printf("Enter the number of ppl u want to spread \r\n");
scanf("%d",&ppl);
while(sum<ppl)
{
sum = pow(3,i);
time = 5 * i;
i++;
}
printf("time in min required is %d \r\n",time);
[
out put:
Enter the number of ppl u want to spread
768
time in min required is 35
]
==================
For your refernce :
1->2 [ total 3 ppl ] took 5 min;
3 -> 6 [ total 9 ppl ] took 10 min
9 ->18 [ total 27 ppl ] took 15 min ..
27 -> 54 [ total 81 ppl ] took 20 min
81 -> 162 [ total 243 ppl ] took 25 min
243 -> 486 [ total 729 ppl ] took 30 min
729 -> 1458 [ total 2187 ppl ] took 35 min
overall it's power of 3
============================
| Is This Answer Correct ? | 19 Yes | 3 No |
Answer / manish panwar
// It's a combination of 1+2+4+8+16+.... and each intervl
takes 5 minutes.
SO
1+2+4+8+16+32+64+128+256+512+1024
11*5 = 55 MINTS IN TOTAL .
| Is This Answer Correct ? | 11 Yes | 5 No |
Answer / bindu
In the first 5 mins three people come to know of the
rumour; including the first person (who is still able to
spread the rumour!), i..e every 5 mins, three times the
people come to know of the rumour. So it just takes 30 mins
for 729 people and 35 mins for 2187 people to know of the
rumour.
| Is This Answer Correct ? | 8 Yes | 2 No |
Answer / bindu
But Pradeep, your logic assumes that the people who have
already passed the rumour in the first 5mins, will not pass
it again in the next 5mins!! In my logic, they keep on
passing it; 1.e. they don't stop after the first time.
| Is This Answer Correct ? | 5 Yes | 0 No |
Answer / usha
Its 45 min becoz the Ist person spreeds rumour to 2person in
5 min. so in next 5 min the 2 person spreads simultaneously
to 4pesons and these steped is continued tel 45min, such as
2+4+8+16+32+64+128+256+512 this indicate at each addition it
take 5min. so the answer is 45min
| Is This Answer Correct ? | 2 Yes | 1 No |
Answer / pradeep
It requires 45 minutes:
Find the logic below:
int time;
for ( int i=0,SpreadRate=1,Ppl=0;Ppl<=768;i++)
{
Ppl = Ppl + SpreadRate;
time = 5 * i;
SpreadRate = SpreadRate * 2;
}
printf("time in min %d \r\n"),time);
| Is This Answer Correct ? | 2 Yes | 3 No |
Answer / pradeep
// It's a combination of 1+2+4+8+16+.... and each intervl
takes 5 minutes.
so use the below logic to find out the ryt answer
int time;
for ( int i=0,sum=0;sum<=768;i++)
{
sum = sum+(2*i);
time = 5*i;
}
printf("time in min %d \r\n"),time);
correct answer is 140 minutes [ nothng but 2 hours 20 min]
return TRUE;
| Is This Answer Correct ? | 4 Yes | 12 No |
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