16.d Combination/ Permutation Extended

Question 1

Solve:

Answer 1

Question 2

Solve:

Answer 2

Question 3

Solve:

Answer 3

Question 4

What is important to see when you are asked about a x-digit number?

Answer 4

Remember that the first digit (hundreds digit) can NOT be 0

Question 5

What should you always do when dealing with restrictive choice?

Answer 5

Begin with the MOST restrictive CHOICE!

Question 6

Explain the order in which you would tackle this:

Answer 6

From MOST to LEAST restrictive

Question 7

What is a “multi-scenario” digit question?

Answer 7

Try solve normally, if you notice its not possible, divide into how many scenarios you need and add the final solutions together

Question 8

How do you think the “multi-scenario” question?

Answer 8

Question 9

Solve:

Answer 9

Question 10

If three or more points can be connected by the same straight line, what would you call it?

Answer 10

Collinear

Question 11

Are there collinear points?

Answer 11

No, given there are no 3 points on the same straight line

Question 12

If there are “n” points on a plane such that no three points are collinear, then we can create a triangle in….

Answer 12

Question 13

Solve this:

Answer 13

Question 14

Solve:

Answer 14

Question 15

Are there collinear points here?

Answer 15

Yes!!
Multiple

Question 16

How would you calculate the number of triangles that can be drawn from these points?

Answer 16

Total # of ways MINUS # of 3 collinear points

(Just count the number of 3 collinear points, horizontal, vertical, diagonal.. all!)

Question 17

What is important to see here:

Answer 17

That THIS is how you calculate the # of collinear points