Answer:
Its (A), 1/9a^2
if you work out all of the other options it does not equal to the expression (3a)^-2
Step-by-step explanation:
If you could write out the whole problem exactly how it is, I can solve it for you.
Since the motor boat left the dock 2 hours before the tour boat, their meeting point will be 27 miles from the dock from which both boats departed after 3 hours.
<h3>What is the distance?</h3>
Distance is the movement of an object regardless of direction. The distance can be defined as the amount of length an object has covered, regardless of its starting or ending position
We know that r × t = d
r = rate of speed
t = time
d = distance
For the motor boat
9 × t = d = rate × time
For the tour boat
27 × (t - 2) = d = rate × time
When they both cover the same distance in the same amount of time, they will eventually cross paths.
They both cover the same d-mile distance, so:
9 ×t = 27 × (t - 2)
Simplify to get:
9 × t = 27 × t - 54
18 t = 54
t = 3
The motor boat will have traveled at 9 mph for 3 hours to make a distance of 9 × 3 = 27 miles.
The tour boat will have traveled at 27 mph for 1 hour to make a distance of 1 × 27 = 27 miles.
Since the motor boat left the dock 2 hours before the tour boat, their meeting point will be 27 miles from the dock from which both boats departed after 3 hours.
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Try this option, modify design according to local requirements.
We have to find the mass of the gold bar.
We have gold bar in the shape of a rectangular prism.
The length, width, and the height of the gold bar is 18.00 centimeters, 9.21 centimeters, and 4.45 centimeters respectively.
First of all we will find the volume of the gold bar which is given by the volume of rectangular prism:
Volume of the gold bar 
Plugging the values in the equation we get,
Volume of the gold bar 
Now that we have the volume we can find the mass by using the formula,

The density of the gold is 19.32 grams per cubic centimeter. Plugging in the values of density and volume we get:
grams
So, the mass of the gold bar is 14252.769 grams