<PRE><B>Question 856571</B>
4-2=2 1
6-2=4 2
8-2=6 3
10-2=8 4
12-2=10 5
14-2=12 6
16-2=14 7
18-2=16 8
20-2=18 9 
22-2=20 10
24-2=22 11
26-2=24 12
28-2=26 13
30-2=28 14 
32-2=30 15
34-2=32 16
36-2=34 17
38-2=36 18
40-2=38 19 
42-2=40 20
44-2=42 21
46-2=44 22
48-2=46 23
50-2=48 24 
52-2=50 25
54-2=32 26
56-2=34 27
58-2=36 28
60-2=38 29 
62-2=40 30
64-2=42 31
66-2=44 32
68-2=46 33
70-2=48 34 
72-2=70 35
74-2=72 36
76-2=74 37
78  out 38 
an = a + (n - 1)d
78 = 4 + 2(n - 1)
78 = 2n + 2
76=2n
38=n





 

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