Question 7 - A-Level Maths

Exam Board	Edexcel
Module	S1 (Statistics 1)
Year	2007
Session	January
Topic	Normal Distribution
Type	Multiple probability calculations

The measure of intelligence, IQ, of a group of students is assumed to be Normally distributed with mean 100 and standard deviation 15.
1. Find the probability that a student selected at random has an IQ less than 91.
The probability that a randomly selected student has an IQ of at least \(100 + k\) is 0.2090 .
Find, to the nearest integer, the value of \(k\).