If he was there at the beginning of this interval, then the Wall must have existed for of its lifespan, and of its lifespan remained. In other words, the Wall would last 3 times as long as it already had existed. If he was there at the end of this interval, then the Wall must have existed for of its lifespan, and only was left. In other words, the Wall would last only as long as it already had existed. The Wall was 8 years old when Gott saw it. He therefore predicted, in the summer of 1969, that there was a 50 % chance of the Wall lasting a further to 24 years ( years to years).
Wow
