Answer:
lower than Amanda: 816 students
Step-by-step explanation:
An equivalent way in which to state this problem is: Find the area under the standard normal curve to the left (below) 940.
Most modern calculators have built in distribution functions.
In this case I entered the single command normalcdf(-1000,940, 850, 100)
and obtained 0.816.
In this particular situation, this means that 0.816(1000 students) scored lower than Amanda: 816 students.