15/2 = $7.5 per hour
7.5 times 5 = $37.50 earned in 5 hours
Answer:
Third option. 
Step-by-step explanation:
For this exercise you need to remember one of the properties for exponents.
There is a property called the "Negative property of exponents" which states the following:
Where 
As you can observe,
is the reciprocal of 
In this case you have the following expression given in the exercise:

Observe the expression. As you can notice, the base "n" has a negative exponent, which is -6.
Therefore, applying the Negative property of exponents explained at the beginning of this explanation, you can simplify the expression.
Then, the simplified form of
is the one shown below:

Answer:
Step-by-step explanation:
hair growth is the bottom one y + 3x
total area is the top one y = 3x²
bacteria is the middle one y = 3ˣ