Respuesta :

The probability of guessing 4 right is
.. (5C4)*(1/2)^5 = 5/32
The probability of guessing 5 right is
.. (5C5)*(1/2)^5 = 1/32

So, the probability of guessing 4 or 5 right is
.. (5+1)/32 = 6/32 = 0.1875