Alright, so it would be helpful to think about this question in terms of units. You're given a distance (meters) and speed (meters per second). You're asked for time (which is in seconds).
If you do
, your answer will be in seconds. So divide your distance (2.28 x 10^11 meters) by your speed (3.00 x 10^8 meters/second), and you should get your time!
What kind of mathematics are you learning?
3x - 3 = 2x
Add 3 on both sides
3x - 3 + 3 = 2x + 3
3x = 2x + 3
Subtract 2x on both sides
3x - 2x = 2x + 3 - 2x
3x - 2x = 3
x = 3
So, your final answer is x = 3.
The definition of the tangent function tells you
tan(angle) = (300 ft) / (distance to mountain)
This equation can be rearranged to
(distance to mountain) = (300 ft) / tan(angle)
For the far end of the river,
distance to far end = (300 ft) / tan(24°) ≈ 673.8 ft
For the near end of the river
distance to near end = (300 ft) / tan(40°) ≈ 357.5 ft
Then the width of the river can be calculated by finding the difference of these distances:
width of river = distance to far end - distance to near end
width of river = 673.8 ft - 357.5 ft
width of river = 316.3 ft
The appropriate answer choice is
316 ft.
