Question

for an A.P d=4 ,a=1 find n if tn=18​

Answer 1

Answer:

Tn = a+(n-1)d

18 = 1+(n-1)4

18 = 1+4n-4

4n = 21

n = 21/4 = 5.25

(Question is wrongly written )

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Answer 2

The value of n will be "21/4".

Step-by-step explanation:

$The \ given \ values \ are:\\d=4\\a=1\\T_{n}=18\\n=?\\As \ we \ know,\\ T_{n}=a+(n-1)d\\ 18=1+(n-1)4\\18=1+4n-4\\18=4n-3\\On \ adding \ "3" \ on \ both \ sides,we \ get\\18+3=4n-3+3\\21=4n\\n=\frac{21}{4}$

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