Question

Which term of the A.P. 3, 8, 13, 18,
is 78?
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Answer 1

Answer:

15th term..............

Answer 2

Step-by-step explanation:

tn=a+(n-1)d

a=3,d=5

tn=3+(n-1)5=78

3+5n-5=78

5n=78+2

5n=80

n=16

16 th term is 78