Test: Geometric Series I - Challenging

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Question 1:   In the geometric series a n itís known that a 10 =2 . Find product of the nineteen first terms of this progression.
2 10
2 19
38
3.8
Question 2:   The second term of the geometric series is a 2 =4 . Find the product of three first terms of this progression.
32
16
64
128
Question 3:   Find the initial term and the common ratio of a geometric series a n , if a 5 =3 a 3 ; a 6 a 2 =48 .
a 1 =2 3 , r= 3
a 1 =0.2 , r= 3
a 1 =2 3 , r= 3 or a 1 =2 3 , r= 3
a 1 =2 3 , r= 3 or a 1 =2 3 , r= 3
Question 4:   Find the initial term and the common ratio of a geometric sequence which consists of 6 terms. The sum of the first three terms is 168 , the sum of the last three terms is 21 .
a 1 =96;r= 1 2  
a 1 165.4; r= 1 4
a 1 147.3; r= 1 8
a 1 =24; r=2
Question 5:   The sum of three positive sequent numbers that make up an arithmetic series a n is 21 . If you add 2, 3, 9 to these numbers, they would make up a geometric series b n . Find these initial numbers.
5, 10, 20
1, 7, 49
3, 7, 11
2, 7, 12
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