A stick of 70 cm breaks in two. At both ends (each 10cm) the stick cannot break. All places where the stick can break are equally likely. What is the probability that the difference between the largest and the smallest part of the stick is at least 10cm?

Answer 1

If the break is x cm from one end, then you want
|x - (70-x)| >= 10
So, either
x <= 30 OR x >= 40
That means there is only an interval of 10cm which will not work.
So, since the total breakable interval is 50cm, there is a 40/50 chance of breaking at an acceptable spot.

Answer 2

thank you