Question

the expression $5 \cdot 1.15^t$ gives the area, in square meters, damaged by a fire as a function of minutes since the fire was discovered.
what does 5 represent in this expression?
choose 1 answer:
a it has been 5 minutes since the fire was discovered.
b the area damaged by the fire is multiplied by 5 each minute.
c an area of 5 square meters had been damaged by the fire by the time it was discovered.

Explanation:

The expression follows the exponential growth form $A(t) = A_0 \cdot r^t$, where $A_0$ is the initial value when $t=0$. Here, $t$ is minutes since discovery, so $t=0$ is the moment the fire was discovered. Substituting $t=0$ gives $5 \cdot 1.15^0 = 5 \cdot 1 = 5$, which is the initial damaged area.

Answer:

C. An area of 5 square meters had been damaged by the fire by the time it was discovered.