Answer:
2.5% of IQ scores are no more than 65
Step-by-step explanation:
The Empirical Rule states that, for a normally distributed random variable:
68% of the measures are within 1 standard deviation of the mean.
95% of the measures are within 2 standard deviation of the mean.
99.7% of the measures are within 3 standard deviations of the mean.
In this problem, we have that:
Mean = 95
Standard deviation = 15
Using the empirical rule, what percentage of IQ scores are no more than 65?
65 = 95 - 2*15
So 65 is two standard deviations below the mean.
By the Empirical Rule, 95% of the measures are within 2 standard deviation of the mean. Of those 5% which are not, 2.5% are more than 2 standard deviations above the mean and 2.5% are more than 2 standard deviations below the mean.
So 2.5% of IQ scores are no more than 65
8y = 4x -16
-x = -2y -4
Multiply all terms in the second equation by -1:
-x = -2y -4 x -1 = x = 2y +4
Now replace x in the first equation with this.
8y = 4(2y+4)
Simplify:
8y = 8y +16
Because there is an 8y on both sides of the equation, it cannot be solved.
The answer is no solution.
