A combination is an unordered arrangement of r distinct objects in a set of n objects. To find the number of permutations, we use the following equation:
n!/((n-r)!r!)
In this case, there could be 0, 1, 2, 3, 4, or all 5 cards discarded. There is only one possible combination each for 0 or 5 cards being discarded (either none of them or all of them). We will be the above equation to find the number of combination s for 1, 2, 3, and 4 discarded cards.
5!/((5-1)!1!) = 5!/(4!*1!) = (5*4*3*2*1)/(4*3*2*1*1) = 5
5!/((5-2)!2!) = 5!/(3!2!) = (5*4*3*2*1)/(3*2*1*2*1) = 10
5!/((5-3)!3!) = 5!/(2!3!) = (5*4*3*2*1)/(2*1*3*2*1) = 10
5!/((5-4)!4!) = 5!/(1!4!) = (5*4*3*2*1)/(1*4*3*2*1) = 5
Notice that discarding 1 or discarding 4 have the same number of combinations, as do discarding 2 or 3. This is being they are inverses of each other. That is, if we discard 2 cards there will be 3 left, or if we discard 3 there will be 2 left.
Now we add together the combinations
1 + 5 + 10 + 10 + 5 + 1 = 32 choices combinations to discard.
The answer is 32.
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Note: There is also an equation for permutations which is:
n!/(n-r)!
Notice it is very similar to combinations. The only difference is that a permutation is an ORDERED arrangement while a combination is UNORDERED.
We used combinations rather than permutations because the order of the cards does not matter in this case. For example, we could discard the ace of spades followed by the jack of diamonds, or we could discard the jack or diamonds followed by the ace of spades. These two instances are the same combination of cards but a different permutation. We do not care about the order.
I hope this helps! If you have any questions, let me know :)
Answer:
44
Step-by-step explanation:
you do 5x7 35 and 6x3 then divided by 2 is 9 and you add them up and you get 44.
Alternate solution. 5x3 divded 2 =7.5 plus 6x3 divided by 2 = 9 plus 7x ? = 27.5!
Answer: C, 20%
Hope this helps
Answer:
47 pizzas
Step-by-step explanation:
Dave makes 6 pizzas in the first hour it is open and 3 pizzas each hour after that.
If the number of hours after the first hour is represented as x, then the number of pizzas he makes after x hours is:
6 + 3x
Lauren makes 11 pizzas in the first hour and 3 pizzas each hour after that. Then:
11 + 3x
The pizzeria is open for 6 hours in all, that is, 5 hours after the first hour.
This means that:
x = 5
The total amount of pizzas that Dave and Lauren make is:
6 + 3x + 11 + 3x
=> 17 + 6x
Therefore, the total amount of pizza they make 5 hours after the first hour is:
17 + 6(5) = 17 + 30 = 47 pizzas
