How many sides does a 2520 degree polygon have?

Answer 1

A friend asked me to think of number add 5 to it and then divided the sum by 20. The result is the same as subtracting 4 from the original number and dividing the difference by 15. What is the number?

Answer 2

It has sixteen sides, the way I worked this out was this:

let n equal the number of sides of the polygon,

normally, the amount of degrees in a polygon equals (n-2)*180, so I changed the equation around to look like this:

n - 2 = 2520/180

=14

therefore,

n = 14+2

n = 16