Question

which term of the A.P. 5, 8, 11, 14 is 320
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Answer 1

AP - 5, 8, 11, ...

A = 5

cd = 8 - 5 = 3

An = 320

we know, An = A + (n-1)cd

              320 = 5 + (n-1)3

              320 = 5 + 3n -3

              320 - 2 = 3n

               318/3 = n

Hence, n is 106

Answer 2

Answer:

106

Step-by-step explanation:

an = 320 ; a = 5 ; d = 3

an = a + (n-1)d

320 = 5 + (n-1)3

315/3 = n-1

n-1 = 105

Therefore, n = 106