JSFiddle - React, Tailwind, and code Playground

JavaScript

var a, b, n = 0, i;
for (i = 0; i < 1000; i++) {
	a = Math.round(Math.random());
	b = Math.round(Math.random());
	//0 орел
	//1 решка
	n += 2;
	while (a != 0 || b != 1) { a = b; b = Math.round(Math.random()); n++; }
}
alert(n / i);