Pls anwser this question pls it’s easy math I really need it look at the pic
1 answer:
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Using the combination formula, it is found that there are 220 ways to decide which countries to skip.
The order in which the countries are skipped is not important, hence the <em>combination formula </em>is used to solve this question.
<h3>What is the combination formula?</h3> is the number of different combinations of x objects from a set of n elements, given by:
In this problem, 3 countries are skipped from a set of 12, hence the number of ways is given by:
More can be learned about the combination formula at brainly.com/question/25821700
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Answer:
see explanation
Step-by-step explanation:
the sum to n terms of an arithmetic sequence is
=
[2a + (n - 1)d ]
where d is the common difference and a is the first term
here d = 9 - 7 = 7 - 5 = 2 and a = 5, hence
=
[(2 × 5) + 2(n - 1) ]
= (10 + 2n - 2)
= (2n + 8)
= n² + 4n
When sum = 165, then
n² + 4n = 165 ← rearrange into standard form
n² + 4n - 165 = 0 ← in standard form
(n + 15)(n - 11) = 0 ← in factored form
equate each factor to zero and solve for n
n + 15 = 0 ⇒ n = - 15
n - 11 = 0 ⇒ n = 11
but n > 0 ⇒ n = 11
Minus both sides by 2m
Minus both sides by k
Divided both sides by 7
Minus both sides by k
Divided both sides by 7