Which term of the AP: 3,8,13,18,.......,is 78 ?

1.	Which term of the AP: 3,8,13,18,.......,is 78 ?
Answer» As we know thatFormula in question Tn= a+(n_1)dTn=78, a=3, n=?, d=8_3=578=3+(n_1)578=3+5n_578+2=5n80=5nn=16

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