Answer
0.2005.
Work Step by Step
$q=1-p=1-0.78=0.22$
$n⋅p=100⋅0.22=22≥5.$
$n⋅q=100⋅0.78=78≥5.$
Hence, the requirements are satisfied.
mean: $\mu=n\cdotp=100\cdot0.22=22.$
standard deviation: $\sigma=\sqrt{n\cdot p\cdot q}=\sqrt{100\cdot0.22\cdot0.78}=\sqrt{3.12}=4.14.$
25.5 is the first one more than 25, hence:
$z=\frac{value-mean}{standard \ deviation}=\frac{25.5-22}{4.14}=0.84.$
By using the table, the probability belonging to z=0.84: 0.7995, hence the probability of z being more than 0.84: 1-0.7995=0.2005.