Question 975617
Find the z score when profit equals zero.
{{{z=(0-50)/45=-1.11}}}
Find the probability associated with that z score.
{{{P=0.13326}}}
.
.
.
{{{z=(x-mu)/(sigma/sqrt(N))=(30-50)/(45/sqrt(25))=-20/9=-2.222}}}
With the corresponding probability, 
{{{P=0.013134}}}
This is the probability that the average is less than 30 so find the complement of the area.
{{{P[c]=1-0.013134}}}
{{{P[c]=0.9869}}}