Good for mr brown. I wish I had a rail card
P(n, r) = n!
____
(n-r)!
= 8!
____
(8-1)!
= 8
An event that cannot happen is impossible
When you see questions of this nature, test the individual inequalities and look out for their intersection.
For
Choose a point in the lower or upper half plane created by the line
The above line is the one which goes through the origin.
Now testing (1,0) yields,
That is,
This statement is true. So we shade the lower half of
For
We test for the origin because, it is not passing through the origin.
This yields
This statement is false so we shade the upper half.
The intersection is the region shaded in B. The top right graph
The smallest value it could be is 4 and the largest value it could be is 10.
The triangle inequality theorem states that any two sides of a triangle must have a sum greater than the third side. Given the two sides we have, 7 and 4, the sum would be 11; this would mean that the missing side could be no more than 10.
If we take the unknown side and the smallest one we're given, we would have the inequality
n+4>7
Subtracting 4 from both sides we would have n>3. That means it would have to be the next integer up, which would be 4.