The Egyptian billionaire

Level pending

Once there was a billionaire who got 1 additional visitor to his touristic resort each day. How many total visitors did he have after 1000 days?


The answer is 500500.

Mohd Sasa by Mohd Sasa , 49, Egypt

This section requires Javascript.
You are seeing this because something didn't load right. We suggest you, (a) try refreshing the page, (b) enabling javascript if it is disabled on your browser and, finally, (c) loading the non-javascript version of this page . We're sorry about the hassle.

3 solutions

Im not sure but i think the problem wasnt clearly stated. I got confused with "he got 1 additional visitor each day". It just means that he gets +1 visitor each day, so at the end of 1000 days he got a total of 1000 only. The problem didnt say that he got 1 more visitor than the previous day. In this case, he had 500500 visitors.

2 Helpful 0 Interesting 0 Brilliant 0 Confused
Mohd Sasa
Apr 27, 2015

The problem is quite clear. All you need is to sum an arithmetic series of the integers of 1 to 1000. Sure you can do it manually, but it will take much time and effort. Here's the formula you need to do it in just 15 seconds: N (n+1) / 2

1000 (1000+1) /2 =

1000 (1001) /2=

1001000 / 2 = 500500

Thanks to the great German mathematician Gauss, we now know that magic formula.

0 Helpful 0 Interesting 0 Brilliant 0 Confused
John Wilcox
Apr 27, 2015

Triangular numbers, (n^2 *n)/2 : 1,3,6,10,15,21,28,36,45,55,66,78,.....

0 Helpful 0 Interesting 0 Brilliant 0 Confused

0 pending reports

×

Problem Loading...

Note Loading...

Set Loading...