Finding Concentration Where Reaction Rates Equal

A scientist is studying the relationship between the concentration of a substance (in mg/L) in a solution and the rate at which it reacts with another substance. The reaction rate (in mg/L/min) can be modeled by the equation:

$$r = 0.5c - 2$$

where:

• $$r$$ is the reaction rate, and
• $$c$$ is the concentration of the substance.

However, if the concentration is lower than 5 mg/L, the reaction rate is affected negatively due to dilution, modeled by:

$$r = -0.3c + 1.5$$

Determine the concentration value, $$c$$, at which both equations give the same reaction rate. Report your answer as a decimal.