820,445 in expanded form: 800,000 + 20,000 + 400 + 40 + 5
A tank with capacity T gallons is empty. Tank will be filled in
minutes
<u>Solution:</u>
Given, A tank with capacity T gallons is empty.
We have to find how many minutes will tank be filled?
Now, Water flows into the tank from pipe X at the rate of X gallons per minute,
And water is pumped out by pipe Y at the rate Y gallons per minute,
Then, together in one minute the amount of water filled will be x – y gallons [as X is greater than Y]
Now, the time take to fill tank = 
Hence tank will be filled in
minutes
The way to find the factores is by seeking the polonomial's roots, or zeros!
To find the roots, we set the polinomial equation to zero:
x^2+16y^2=0
Then we solve this equation:
x^2=-16y^2
This is only true, if x=y=0.
The answer is the first choice.
P(both even) = (4P1)(3P1) / 9P2