Question

Which term if AP 4,12,20,28...will be 120 more than 21st term

Answer 1

_T21 = a + 20.
(20×8)
T21 = 4 + 160
T21 =164..

120 more than 21st term = 164+120
= 284...
Now,

284 = a + (n-1)d

284 = 4 + (n-1)8
284 = 4 + 8n -8
284 = 8n - 4
284+4 = 8n
288÷8 = n
36 =n


•°•The answer is 36th term...

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