If Five Arithmetic Means Are Instead Between -9 And 9 . What Is The Third Mean ? With Solution By Using This Formula

if five arithmetic means are instead between -9 and 9 . what is the third mean ? with solution by using this formula

 

Answer:

3rd Arithmethic mean is 0

Five arithmethic mean between

-9,_,_,_,_,_,9

a1=-9

an=9

n=7

d=?

find d

using an=a1+(n-1)d,

substitute

9=-9+(7-1)d

9=6d−9

6d=18

d=3

Find 3rd mean

-9,_,_,(_),_,_,9

Find a4

an=a1+(n-1)d

a1=-9

n=4

d=3

a4=-9+(4-1)3

a4=−9+(3)(3)

a4=−9+9

a4=0

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