-3.
It's the same as normal division unless they have different signs, then it's negative.
Answer:

2.22%
Step-by-step explanation:
$8400 is invested in an account earning 2.2% interest (APR), compounded monthly.
So, the value of the account after t years will be given by
{Rounded to the four decimal places} (Answer)
Now, for t = 1 year, f(1) = $8586.67
So, the percentage of growth per year (APY) =
% {Rounded to the nearest hundredth of percent} (Answer)
You get a "sum" when you add numbers together.
For there to be 1 car, we consider two possible outcomes:
The first door opened has a car or the second door opened has a car.
P(1 car) = 2/6 x 4/5 + 4/6 x 2/5
P(1 car) = 8/15
For there to be no car in either door
P(no car) = 4/6 x 3/5
P(no car) = 2/5
Probability of at least one car is the sum of the probability of one car and probability of two cars:
P(2 cars) = 2/6 x 1/5
= 1/15
P(1 car) + P(2 cars) = 8/15 + 1/15
= 3/5