Answer:
0.2109 or 21.09%
Step-by-step explanation:
In order to maintain the same price after two days, the stock must go up (U) on two days and go down (D) on two days, the sample space for this event is:
S={UUDD, UDUD, UDDU, DDUU, DUDU, DUUD}
There are 6 equally likely possible outcomes. The probability that the price of the stock will be the same as it is today is:
The probability is 0.2109 or 21.09%.