Why did we add 1 to each term?
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In how many ways can a manager of a chain of a supermarkets divide between two of its branches 100 units of one product, 200 of another, 150 of a third, and 11 of a fourth? [Notice divide means no branch is left without products]
Solution
(100+1)·(200+1)·(150+1)·(11+1)−2
Of the first product, the manager can assign k = 0, · · · , 100 units to one of the branches, and so for the other products. Since the products must be divided between the two branches, then we should not count the cases where all products are assigned to one branch.However, I don’t understand why we added 1 to each term?
probability statistics
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up vote
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In how many ways can a manager of a chain of a supermarkets divide between two of its branches 100 units of one product, 200 of another, 150 of a third, and 11 of a fourth? [Notice divide means no branch is left without products]
Solution
(100+1)·(200+1)·(150+1)·(11+1)−2
Of the first product, the manager can assign k = 0, · · · , 100 units to one of the branches, and so for the other products. Since the products must be divided between the two branches, then we should not count the cases where all products are assigned to one branch.However, I don’t understand why we added 1 to each term?
probability statistics
add a comment |Â
up vote
1
down vote
favorite
up vote
1
down vote
favorite
In how many ways can a manager of a chain of a supermarkets divide between two of its branches 100 units of one product, 200 of another, 150 of a third, and 11 of a fourth? [Notice divide means no branch is left without products]
Solution
(100+1)·(200+1)·(150+1)·(11+1)−2
Of the first product, the manager can assign k = 0, · · · , 100 units to one of the branches, and so for the other products. Since the products must be divided between the two branches, then we should not count the cases where all products are assigned to one branch.However, I don’t understand why we added 1 to each term?
probability statistics
In how many ways can a manager of a chain of a supermarkets divide between two of its branches 100 units of one product, 200 of another, 150 of a third, and 11 of a fourth? [Notice divide means no branch is left without products]
Solution
(100+1)·(200+1)·(150+1)·(11+1)−2
Of the first product, the manager can assign k = 0, · · · , 100 units to one of the branches, and so for the other products. Since the products must be divided between the two branches, then we should not count the cases where all products are assigned to one branch.However, I don’t understand why we added 1 to each term?
probability statistics
asked Jul 27 at 18:56
Roy Rizk
887
887
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1 Answer
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"Of the first product, the manager can assign $k = 0, dots , 100$ units to one of the branches"
Indeed. So this is $lvert 0,1,2,dots,100rvert = 101$ options for $k$ (the number of products of the first type put into the first branch can be zero).
Same for the other 3 products. So you get
$$
(100+1)(200+1)(150+1)(11+1)
$$
possible assignments for the first branch (and, obviously, an assignment to the first branch fully determines the assignment to the second branch: the rest of the products).
Now, there is the remaining $-2$. Why? Because
divide means no branch is left without products
so you must remove the two solutions corresponding to $0$, or all, products assigned to the first branch.
Thus, overall, you obtain
$$
(100+1)(200+1)(150+1)(11+1)-2
$$
possible assignments.
add a comment |Â
1 Answer
1
active
oldest
votes
1 Answer
1
active
oldest
votes
active
oldest
votes
active
oldest
votes
up vote
3
down vote
accepted
"Of the first product, the manager can assign $k = 0, dots , 100$ units to one of the branches"
Indeed. So this is $lvert 0,1,2,dots,100rvert = 101$ options for $k$ (the number of products of the first type put into the first branch can be zero).
Same for the other 3 products. So you get
$$
(100+1)(200+1)(150+1)(11+1)
$$
possible assignments for the first branch (and, obviously, an assignment to the first branch fully determines the assignment to the second branch: the rest of the products).
Now, there is the remaining $-2$. Why? Because
divide means no branch is left without products
so you must remove the two solutions corresponding to $0$, or all, products assigned to the first branch.
Thus, overall, you obtain
$$
(100+1)(200+1)(150+1)(11+1)-2
$$
possible assignments.
add a comment |Â
up vote
3
down vote
accepted
"Of the first product, the manager can assign $k = 0, dots , 100$ units to one of the branches"
Indeed. So this is $lvert 0,1,2,dots,100rvert = 101$ options for $k$ (the number of products of the first type put into the first branch can be zero).
Same for the other 3 products. So you get
$$
(100+1)(200+1)(150+1)(11+1)
$$
possible assignments for the first branch (and, obviously, an assignment to the first branch fully determines the assignment to the second branch: the rest of the products).
Now, there is the remaining $-2$. Why? Because
divide means no branch is left without products
so you must remove the two solutions corresponding to $0$, or all, products assigned to the first branch.
Thus, overall, you obtain
$$
(100+1)(200+1)(150+1)(11+1)-2
$$
possible assignments.
add a comment |Â
up vote
3
down vote
accepted
up vote
3
down vote
accepted
"Of the first product, the manager can assign $k = 0, dots , 100$ units to one of the branches"
Indeed. So this is $lvert 0,1,2,dots,100rvert = 101$ options for $k$ (the number of products of the first type put into the first branch can be zero).
Same for the other 3 products. So you get
$$
(100+1)(200+1)(150+1)(11+1)
$$
possible assignments for the first branch (and, obviously, an assignment to the first branch fully determines the assignment to the second branch: the rest of the products).
Now, there is the remaining $-2$. Why? Because
divide means no branch is left without products
so you must remove the two solutions corresponding to $0$, or all, products assigned to the first branch.
Thus, overall, you obtain
$$
(100+1)(200+1)(150+1)(11+1)-2
$$
possible assignments.
"Of the first product, the manager can assign $k = 0, dots , 100$ units to one of the branches"
Indeed. So this is $lvert 0,1,2,dots,100rvert = 101$ options for $k$ (the number of products of the first type put into the first branch can be zero).
Same for the other 3 products. So you get
$$
(100+1)(200+1)(150+1)(11+1)
$$
possible assignments for the first branch (and, obviously, an assignment to the first branch fully determines the assignment to the second branch: the rest of the products).
Now, there is the remaining $-2$. Why? Because
divide means no branch is left without products
so you must remove the two solutions corresponding to $0$, or all, products assigned to the first branch.
Thus, overall, you obtain
$$
(100+1)(200+1)(150+1)(11+1)-2
$$
possible assignments.
answered Jul 27 at 19:05


Clement C.
47k33682
47k33682
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