Question

1. If three arithmetic means are inserted between — 15 and 9, What is the first of the arithmetic.

A. 3
B. - 3 
C. - 9 
D. 6​

Answer 1

Answer

First term =-15

Second term is 9

Tn=a×(n-1)d

If you insert 3 arithmatic means between them 9 WIILL be T5 of AP

T5=T1+(5-1)×d

9=T1+4d

9=-15+4d

4d=24

d=6

a=--15 d=6

The terms of AP are

-15 -15+6 - 15 +2×6 -15 +3× 6 -15+4×6

-15 -9 -3 3 9

First AM is --9

Explanation step by step

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