Question 1122525
z=(x-mean)/sd
top 10% is 0.9000 in the z-table, and z=1.28
therefore 1.28=(x-mean)/sd for cut off top score
1.28=(x-mean)/12
15.36=x-72
x=87.36, cut off for top score

Bottom 20% (draw std normal curve) is at z=-0.84
so-0.84=(x-72)/12
-10.08=x-72
x=61.92, cut off score below which remedial must be attended.