Find P90, which is the IQ score separating the bottom 90% from the top 10%.

IQ Scores. In Exercises 13–20, assume that adults have IQ scores that are normally distributed with a mean of 100 and a standard deviation of 15 (as on the Wechsler test).
For a randomly selected adult, find the indicated probability or IQ score. Round IQ scores to the nearest whole number. (Hint: Draw a graph in each case.)