Originally Posted by

**slyone** Hi,

Can someone please help with this. I keep getting different answers to this from different people.

Supposing you have a weighted coin which lands heads up 70% of the time and tails up 30% of the time.

Q. What is the probability that it lands on **tails 20 or more** **times ****in a row** if I did this **1000 **times?

*Also could I have the equation on how you worked this out so that I can change the weighting, number of trials etc (I need to know this for my business!!!)

Thank you very much.

Zak