Answer Happy

Authorities conducted an investigation and found that the
chemical Trioxin was illegally dumped into the local swamp. Exactly
four days after the assumed time of the​ crime, the amount of
Trioxin in the swamp was estimated at about 39.6 ​barrels, and
exactly seven days after the​ crime, it was estimated at 31.1
barrels.  Assume that no Trioxin was in the swamp before
the​ crime, and that Trioxin decays exponentially. Construct a
model that estimates the amount of Trioxin​ (in barrels)
remaining in the swamp t days after it was​ dumped, then use
that model to answer the following.
​1) According to the​ model, how much Trioxin was initially
dumped into the​ swamp?
ROUND TO ONE DECIMAL PLACE.
About _______barrels were initially dumped into the swamp.
​2) According to the​ model, at what rate was the amount of
Trioxin in the swamp decreasing exactly 4 days after it
was​ dumped?  ROUND TO ONE DECIMAL PLACE.
The Trioxin was decreasing at a rate of ____barrels per day.
​3) How many days after the crime​ will/did it take for the
amount of Trioxin in the swamp to drop to 2​ barrels?  ROUND
TO ONE DECIMAL PLACE.
It took or will take about _______days.