Test: Arithmetic Series I - Ambitious

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Question 1:   Find the formula of the n-th term of an arithmetic progression b n : a+3, a+1, a1, a3,
b n =a2n+1
b n =a2n+5 
b n =a+2n+1
b n =a2n+4
Question 2:   In the arithmetic progression ( a n ): a 1 =1;d=2.5 . Is 13.5 a term of this progression? If yes, find its number.
13.5 is not a term of this progression
n=13
n=6
n=5
Question 3:   Find the initial term of the arithmetic sequence ( a n ), if b 5 =11;  b 11 =7 .
a 1 =23
a 1 =19
a 1 =26
More data is needed
Question 4:   What is the number of the first positive term of an arithmetic sequence ( a n ): 10.2;9.5;8.8; …?
n=15
n=14
n=16
n=10
Question 5:   Find the first negative term of an arithmetic sequence ( a n ): 7.2;6.6;6 .
0.6
0.1
1.8
1.2
Question 6:   Find the fourth term of an arithmetic progression ( a n ) if a 2 =4.5;  a 7 =3 .
a 4 =1.5
a 4 =3
a 4 =2
a 4 =0
Question 7:   The formula of an arithmetic progression ( a n ) is a n =2n+1 . Find the sum of the first twenty terms of this progression.
s 20 =200
s 20 =800
s 20 =400
s 20 =380
Question 8:   Find the sum of first fifteen terms of an arithmetic sequence ( a n ), if a 10 =44;d=4 .
s 15 =504
s 15 =1080
s 15 =540
s 15 =510
Question 9:   How many times ( N ) a clock would stroke during a day if it strokes only integer amount of hours from 1 to 12 ?
N=24
N=156
N=12
N=78
Question 10:   Find the sum of all two-digit numbers that are multiples of 6 .
804
810
1620
816