X<20-5y (the whole expression divided by 3)
The astronomer has to choose 3 star images out of 8.This is a problem of combinations. This can be expressed as 8C3 i.e. combination of 8 objects taken 3 at a time.
This means, if 8 images are nearby the astronomer will have 56 choices <span>
of the three stars.</span>
It's B) A straight line can be drawn through all the points and the line passes through the point (0,0)
This is because in the problem it says that the points are paired and proportional. For example, say you're given the point (3,6). To make this a proportional relationship, you'd have another point in the third quadrant: (-3,-6). When you draw a line from one of these points to the other, it passes through the origin.
Arrange the data set from least to greatest:
{45, 58, 70, 100, 450, 600, 805}
Find the median by canceling out until 1 or 2 values remain in the middle of the set:
{58,70,100,450,600}
{70,100,450}
{100}
The one value left is our median
