Given:
The geometric sequence is:

1 -4
2 20
3 -100
To find:
The explicit formula and list any restrictions to the domain.
Solution:
The explicit formula of a geometric sequence is:
...(i)
Where, a is the first term, r is the common ratio and
.
In the given sequence the first term is -4 and the second term is 20, so the common ratio is:



Putting
in (i), we get
where 
Therefore, the correct option is B.
By definition of percentages, we conclude that Montraie has 10 coins saved in his box that come from a collection with a total of 50 coins.
<h3>How to calculate the quantity of coins in a collection</h3>
In this question we know the quantity of coins in a box and such coins are part of the <em>coin</em> collection. By definition of percentage we have the <em>total</em> quantity of coins in the collection:
x = 10*(100/20)
x = 50
By definition of percentages, we conclude that Montraie has 10 coins saved in his box that come from a collection with a total of 50 coins.
To learn more on percentages: brainly.com/question/13450942
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Answer:
750 total people
Step-by-step explanation:
25 to 50 = 1/2
So: 250 x 2 = 500 men
500 + 250 = 750 total