Question

# Write first-order differential equations that express the situation: A student in an engineering course finds the rate of increase of his grade point

First order differential equations
The rate of his grade point average G is $$\frac{dG}{dt}$$ and the word "increasing ” indicates that the constant k will be positive . Also, $$\displaystyle{\frac{{{d}{G}}}{{{\left.{d}{t}\right.}}}}$$ is directly proportional to N and inversely proportional to A indicates that N will be the numerator and A the denominator.
$$\frac{dG}{dt}=\frac{kN}{A},(k>0)$$