Thread: Chain Mail Problem

Hi can anyone help me with this question pls? thank you!


On 1st January the manager of a large organisation learns that the company is about to be taken
over. He sends emails to five colleagues to inform them of the news.
On 2nd January these five colleagues each send out five emails informing other colleagues.
On 3rd January those colleagues who heard the news on the 2nd January each send out four
emails informing other colleagues.
On 4th January those colleagues who heard the news on 3rd January each send out ten emails
informing other colleagues.
On the first three days that the rumour of this take-over was being spread, recipients of the
information only received one email each. On the 4th January, however, two-thirds of recipients
received emails from two different colleagues informing them of the news. The remainder just
received one email.
How many colleagues received two emails on the 4th January?
A 200
B 300
C 400
D 500
E 600


ans C

It would be great to see your development of the string of emails.

Jan 0 - 1 Colleague
Jan 1 - +5 Total 6
Jan 2 - +25 Total 31

What's next?

Jan 3- +100 total 131
Jan 4- +1000 total 1131

is that so?

That's the way I read it. Now what?

There were 1000 emails. Where did they go?