statistics
posted by Michelle .
Entry to a certain University is determined by a national test. The scores on this test are normally distributed with a mean of 500 and a standard deviation of 100. Tom wants to be admitted to this university and he knows that he must score better than 70% of the students who took the test. What should Tom's score at least be in order to be admitted.
NOTE: WRITE YOUR ANSWER USING 4 DECIMAL DIGIT. FOR EXAMPLE 0.1234 OR 3.2450. DO NOT ROUND UP OR DOWN THE LAST DECIMAL DIGIT.

42324213

Z = (scoremean)/SD
Find table in the back of your statistics text labeled something like "areas under normal distribution" to find the proportion (.70) in larger portion and its Z score. Insert the Z score in the above equation to find the score. 
so the equation would be..
.7580=(x500)/100
but i'm not getting a clear answer.