CurioQ Latest Questions

kenny
  • 1
  • 1

How many heads do you expect her to have when she is finished all 200 tosses?

  • 1
  • 1

A friend of yours plans to toss a fair coin 200 times. You watch the first 20 tosses and are surprised she got 15 heads. But then you get bored and leave.

How many heads do you expect her to have when she has finished all 200 tosses?

Leave an answer

Leave an answer

h

  1. Expected Number of Heads after 200 Tosses

    Since the coin is fair, the probability of getting heads on each toss is 0.5. Over 200 tosses, the expected number of heads is:

    200 tosses × 0.5 = 100 heads

    However, you’ve already observed 15 heads in the first 20 tosses. This leaves 180 tosses remaining. For these remaining tosses, the expected number of heads is:

    180 tosses × 0.5 = 90 heads

    Thus, the total expected number of heads after all 200 tosses is:

    15 (from the first 20 tosses) + 90 (from the remaining 180 tosses) = 105 heads