permutations question

[saigopal7]

Pat's pizza offers thick,thin, or deep-dish style crust.There are 8 choices for toppings.

In how many ways can u choose a pizza with three different toppings?


Ans:1008

[800guy]

this is a permutations problem

number of permutations for ONE pizza:
8P3 =

8! divided by (8 - 3)! = 336

multiply this by 3 since there are 3 types of crust

336 x 3 = 1008

hope this helps!!

[projase]

Why is this a permutation and not a combination problem?

For me the solution is 3x 8C3.....

this is a permutations problem

number of permutations for ONE pizza:
8P3 =

8! divided by (8 - 3)! = 336

multiply this by 3 since there are 3 types of crust

336 x 3 = 1008

hope this helps!!

[800guy]

you're right projase

i think this should be a combinations problem after all. somehow i got the right answer though using the permutations equation

[one_pacifist]

hi all

new to permutations and combinations topic, so need help on this ....

q) A set of 6 questions contains true /false type questions.
Maximum how many students can take the test if all the students answer differently from others and must attempt all the questions ?

a gud explanation on answer will help a lot!!!!!!

[Night reader]

Pat's pizza offers thick,thin, or deep-dish style crust.There are 8 choices for toppings.

In how many ways can u choose a pizza with three different toppings?


Ans:1008

8P3 * 3!=8!/(8-3)! *3=1008

call pizzas: thick-x,thin-y, deep-dish-z

x, y or z can be chosen in 8 ways as the first order
x, y or z can be chosen in 7 ways
x, y or z can be chosen in 6 ways
(8*7*6) *3=1008

[rohu27]

Nightreader,

Please clarify this one.
we are asked to choose a single pizza wth 3 diff toppings.
no. of ways to choose 3 toppings out of 8 is 8c3.
as the no. of crusts are 3, total combnations are: 3*8c3=168 combinations.

or is it tht we need to consider a thin crust pizza wth ABC toppings diff frm a thin crust pizza wth BAC toppgs?

Totally confused

Pat's pizza offers thick,thin, or deep-dish style crust.There are 8 choices for toppings.

In how many ways can u choose a pizza with three different toppings?


Ans:1008

8P3 * 3!=8!/(8-3)! *3!=2116 this should be the correct answer in reality

or call pizzas: thick-x,thin-y, deep-dish-z

x, y or z can be chosen in 8 ways as the first order
x, y or z can be chosen in 7 ways
x, y or z can be chosen in 6 ways
(8*7*6) *3!=2116

[Night reader]

I've edited the previous solution; the problem doesn't explicitly state the topping order, so I assumed that ABC is different from BAC
if the topping order doesn't matter than 3*6C3 if it does matter then 3*6P3

Nightreader,

Please clarify this one.
we are asked to choose a single pizza wth 3 diff toppings.
no. of ways to choose 3 toppings out of 8 is 8c3.
as the no. of crusts are 3, total combnations are: 3*8c3=168 combinations.

or is it tht we need to consider a thin crust pizza wth ABC toppings diff frm a thin crust pizza wth BAC toppgs?

Totally confused

Pat's pizza offers thick,thin, or deep-dish style crust.There are 8 choices for toppings.

In how many ways can u choose a pizza with three different toppings?


Ans:1008

8P3 * 3!=8!/(8-3)! *3!=2116 this should be the correct answer in reality

or call pizzas: thick-x,thin-y, deep-dish-z

x, y or z can be chosen in 8 ways as the first order
x, y or z can be chosen in 7 ways
x, y or z can be chosen in 6 ways
(8*7*6) *3!=2116