Check whether ` 150` is a term of the AP : 11, 8, 5, 2...

Explanation

given `a=11`

b=`8-11=5-8= -3`

lets say -150 is `r^(th) term`

so`a+(r-1)d= -150`

`11+(r-1)(-3)= -150`

`(r-1)*3= 161`

`r-1=161/3`

`r=161/2 +1 cancel(=) ` integer

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