Determine the ap whose third term is 15 and difference of 5th than 8th is 21
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Step-by-step explanation:
in AP nth term = a + (n-1)d
3rd term = a +2d
difference between 8th & 5th term
a + 7d - (a + 4d) = 21
a + 7d - a - 4d = 21
3d = 21
d = 7
3rd term,
a + 2d = 15
a + 2*7 = 15
a = 1
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