Question

the sum of first 12 term of arithmetic sequence is 606 what is the first term if the last term is 67 and the common difference is 3
need ko today plss​

Answer 1

Step-by-step explanation:

Given,

Sn= 606

n=12

last term(l) = 67

Common difference(c.d.) =3

$s12 = \frac{n}{2} (a + l) \\ 606 = \frac{12}{2} (a + 67) \\ 606 = 6(a + 67) \\ 606 = 6a + 402 \\ 606 - 402 = 6a \\ 204 = 6a \\ a = \frac{204}{6} \\ a = 34 \\ hence \: first \: term \: is \: 34$

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