The number of housing starts in the Southwest, N(t) in units of a million over the next five years is related to the mortgage rate r(t) in percent per year by the equation 9N^2+r =36. What is the rate of change of the number of housing starts with respect to time when the interest rate is 6% per year and is increasing at the rate of 1.5% per year?

Note: Do not change the percent values given to decimals.

Instructions:
Determine dn/dt
The value for dr/dt is given
The interest rate is given
You will also have to solve for the values of N

Question

The number of housing starts in the Southwest, N(t) in units of a million over the next five years is related to the mortgage rate r(t) in percent per year by the equation 9N^2+r =36. What is the rate of change of the number of housing starts with respect to time when the interest rate is 6% per year and is increasing at the rate of 1.5% per year?

Note: Do not change the percent values given to decimals.

Instructions: 
Determine dn/dt
The value for dr/dt is given
The interest rate is given
You will also have to solve for the values of N