120 likes | 302 Views
The Ice Cream Social. Caught Doing Something Good? Join us for an Ice Cream Social. Choose tw0 toppings: Chocolate syrup Whipped cream Nuts Cherries Pineapple. Choose one flavor of ice cream Chocolate Vanilla Strawberry. THE Ice Cream Social.
E N D
Caught Doing Something Good? Join us for an Ice Cream Social Choose tw0 toppings: Chocolate syrup Whipped cream Nuts Cherries Pineapple Choose one flavor of ice cream Chocolate Vanilla Strawberry
THE Ice Cream Social • Rewarded with an ice cream social, students may select one flavor of ice cream and two toppings. • There are three flavors of ice cream and five toppings to choose from. How many combinations of ice cream and toppings are possible? • What is the probability that you will correctly guess the combination a student will order?
To VISUALizE the Sample Space you can Create a Tree Diagram Choose a flavor of ice cream
To VISUALizE the Sample Space you can Create a Tree Diagram Choose the first topping
To VISUALizE the Sample Space you can Create a Tree Diagram 4 choices Choose the second topping 3 choices Chocolate 2 choices 1 choices 0 choices 10 Total choices
To VISUALizE the Sample Space you can Create a Tree Diagram The same choices can be made for vanilla Vanilla
To VISUALizE the Sample Space you can Create a Tree Diagram and for strawberry, for a total of 3 x 10 or 30 choices. Strawberry
Determine the sample space • If we could use the multiplication rule for this problem, we would have. • 3 Ice cream flavor s • x 5 choices for the 1st topping • x 4 choices for the 2nd topping • Total possible combinations is • 3 x 5 x 4 = 60 • However, the tree diagram reveals there are only 30 unique choices. • The probability of guessing the order correctly is 1/30. This problem involves the MULTIPLICATION RULE and a COMBINATION. The number of combinations of 3 ice cream flavors and 5 toppings , taken 2 at a time, is 3 x 5C2 = 3 x 5! = 3 x 5!___ = 3 x 5 x 4 x 3 x 2 x 1 = 30 2!(5-2)! 2!(3)! 2 x 1 x 3 x 2 x 1
MULTIPLICATION RULE AND COMBINATIONS • Suppose students may choose a third topping . What is the size of the new sample space.? • Rather than completing the tree, you can use the combination formula to calculate the size of the sample space. • 3 Ice cream flavor s • x 5 toppings taken 3 at a time. • Total possible combinations is 30 The number of combinations of 3 ice cream flavors and 5 toppings , taken 3 at a time, is 3 x 5C3 = 3 x 5! = 3 x 5!___ = 3 x 5 x 4 x 3 x 2 x 1 = 30 3!(5-3)! 3!(2)! 3 x 2 x 1 x 2 x 1
Extension Problem • Marble Slab is famous for its flavors and toppings. How many combinations are possible if the High School moves its ice cream social to Marble Slab. • To calculate the number of samples, you need to know the number of flavors and the number of toppings. Visit the Marble Slab site to find out. Assume all the flavors and toppings are available.
MARble Slab • There are 67 ice cream flavors and 68 toppings. • If all the flavors and toppings are available, • The number of combinations of 67 ice cream flavors and 68 toppings , taken 2at a time, is • 67 x 68C2 = ? • A problem of this magnitudes calls for a little help from technology.