About 9% of the population has a particular genetic mutation. 100 people are randomly selected. Find the standard deviation for the number of people with the genetic mutation in such groups of 100. Preview

The two equations are:

y = 5*x + 3

y = 5.5*x + 2

Step-by-step explanation:

By definition:

speed = distance/time

it can be rewritten as:

time = distance/speed

During the first half of the race Ben ran at a rate of 5 miles per hour for x hours and walked 3 miles. Let's call y, the number of miles in half the race; then he ran y-3 miles. The time he spend was:

x = (y-3)/5

Analogously, for the second half:

x = (y-2)/5.5

These two equations can be rewritten as

y = 5*x + 3

y = 5.5*x + 2

Which means that:

5*x + 3 = 5.5*x + 2

3-2 = 5.5*x -5*x

1 = 0.5*x

x = 2 hours

When you are solving for the variables in a situation represented by two equations you can isolate the same variable in both equations and equate the two terms, getting a new equation with only one variable. Another option is to isolate one variable in one equation and replace it in the other one.