no number can have a positive and a negative at the same time. a negative number has a negative sign and a positive number has a plus sign.
Answer:

Step-by-step explanation:
Since P(t) increases at a rate proportional to the number of people still unaware of the product, we have
Since no one was aware of the product at the beginning of the campaign and 50% of the people were aware of the product after 50 days of advertising
<em>P(0) = 0 and P(50) = 1,500,000
</em>
We have and ordinary differential equation of first order that we can write
The <em>integrating factor </em>is
Multiplying both sides of the equation by the integrating factor
Hence
Integrating both sides
But P(0) = 0, so C = -3,000,000
and P(50) = 1,500,000
so
And the equation that models the number of people (in millions) who become aware of the product by time t is
ANSWER
$1,413.81
EXPLANATION
The compound interest formula is given by:

Where P=900 is the balance in the account, t=10 is the number of years and r=0.0462 is the rate.
We substitute the values in to the formula to get:


This simplifies to:

Therefore $1413.81 will be in the account after 10 years.
There were 15 gallons of water to begin with. hope this helps