### Home > CALC > Chapter 7 > Lesson 7.3.2 > Problem7-121

7-121.

Which of the following differential equations could model a population whose rate of change is proportional to the existing population? Explain your reasoning. Is it possible that there is more than one answer?

1. $\frac { d P } { d t }= 3P$

1. $\frac { d P } { d t }= 3t$

1. $\frac { d P } { d t }= −3P$

1. $\frac { d P } { d t }= 3$

A proportional situation follows the patten: $y = kx$.