the first two questions were ok, probability of her passing = pass first time + (fail and pass 2nd time)
then the second part of question 1 you had to rearrange to find the probabilty of him passing 2nd time because you were only given probabilty of passing.
quesiton 2, s.d stayed the same, and the mean was 124.8 100 more. part b ermm was on discussing the heights which involves abit of waffling and part c was to calculate the new mean so you times 124.8 by 50 to get sum of x, and then the other mean by 100 to get the other sum of x, add them together and divide by total which was 150. i think thats right but feel free to correct me..