Answer:
18.5 meters
Step-by-step explanation:
To find the value of the depth in meters, after mr. Mole had been digging for 5 minutes, t should be replaced with 5 in the formula.
[tex]B(t)=-2.3t-7\\B(5)=-2.3(5)-7\\B(5)=-11.5-7\\B(5)=-18.5[/tex]
The value is negative, because Mr. Mole is digging downward. That means that after 5 minutes Mr. Mole had dug 18.5m downward.