Answer:
Step-by-step explanation:

Answer:
482
Step-by-step explanation:
We can see that the numbers shown resemble an arithmetic sequence because they have a common difference. The formula for the nth term of an arithmetic sequence is:

Where
is the first term,
is the nth term, and
is the common difference. To find the 61st term, all we need is the first term and the common difference. By looking at what given, we can say the first term is 2. Now, to find the common difference, we find the difference of a term from the term before it. In this case we can do
, which is
, or the common difference. Since we have everything we need, it can be plugged into the equation:

So, the 61st term is 482.
Answer:

Step-by-step explanation:
I assume that the three points given are the vertices of the triangle. So the three points are:
A (-4,1)
B (-7,5)
C (0,1)
The area of a triangle is given by:

where b is the base and h is the height.
Here we can take as follows:
- We can take the base to be the side AC, so that its length is equal to the distance between the two points:

- The height of the triangle is therefore the perpendicular distance between AC and point B. This is equivalent the difference in the x-coordinate between any point on AC and B, so:

Therefore, the area of the triangle is:

Going upstream: 432 km / 6 hours = 72 km/h
Going downstream: 384 km / 4 hours = 96 km/h
Going upstream against the current means that the effective speed is:
r_boat - r_current = 72
Meanwhile, going downstream with the current means;
r_boat + r_current = 96
Adding both equations (to cancel out r_current) gives:
2r_boat = 72 + 96
r_boat = 84 km/h
Substituting back into one of the original equations: r_current = 12 km/h.