Answer:
A. 15:25 & C. 3:5 would be the ratios that are equivalent to 60%
Answer: 0.6827
Step-by-step explanation:
Given : Mean IQ score : 
Standard deviation : 
We assume that adults have IQ scores that are normally distributed .
Let x be the random variable that represents the IQ score of adults .
z-score : 
For x= 90

For x= 120

By using the standard normal distribution table , we have
The p-value : 

Hence, the probability that a randomly selected adult has an IQ between 90 and 120 =0.6827
0.043 is the correct answer :$