A. Mean is 115 s.d. = 12 100 score will be 15 points below the mean , or 15/12 = 1.25 standard deviations below the mean
Look at you table of negative z-scores and find the number corresponding to -1.25 z = .1056
.1056 x 100 % = 10.56% with score below 100
B. Greater than 130 is 15 points above the mean 15/12 = 1.25 ABOVE the mean
look at your positive z-score table for z-score =1.25 .8944 of the students had a score LESS than this
so 1 - .8944 = .1056 or 10.56% were higher than 130
C calculate the z score less than 110 calculate the z score less than 130
z130 - z110 = fraction between 130 and 100
D. FInd z for 75 ( 115 - 75 = 40 BELOW 40/12 = - 3.33 z ) from neg z-score table
E. Find positive z-score = .9900 (9901 is the closest in my table) this equals z -score 2.33
2.33 x 12 s.d. = 27.96 then 115 + 27.96 = 142.96 to be 1%