Answers

2016-06-27T20:38:30+08:00
There are 13 terms. just add the common difference '4' to the first term till it reaches the last term.
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2016-06-28T18:14:02+08:00
An = a₁ + (n-1)d
59 = 3 + (n-1)4
59 = 3 +4n -4
59 = 4n -1
59 +1 = 4n
60 = 4n
15 = n
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