Answer:
1 minute
Explanation:
To determine when the two substances will reach the same temperature, we can set up equations for their temperatures in terms of time (t).
Substance A is currently 96.2 degrees and its temperature is increasing at a rate of 1.5 degrees each minute. Therefore, the equation that models this is:

Substance B is currently 98.5 degrees and its temperature is decreasing at a rate of 0.8 degrees each minute. Therefore, the equation that models this is:

To determine when the temperatures of the two substances will become equal, simply set the equations equal to each other and solve for t.

Therefore, substances A and B will be at the same temperature after 1 minute, at which time both substances will be 97.7 degrees.