The 19th term of an AP is equal to 3 times its 6th term. If its 9th term is 19, find the AP.
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Answered by
15
Let the first term of the AP be a.
Let common difference be d
a+(19-1)d=3(a+(6-1)d)
=a+18d=3a+15d
=2a=3d
=d=2a/3
Now a+(9-1)d=19
=a+8d=19
=a+8*2a/3=19
=3a+16a=57
=19a=57
=a=57/19
=3
2a=3d
3d=2*3
=3d=6
=d=6/3=2
AP=a,a+d,a+2d,....
=3,5,7,9......
Hope you got your answer
Answered by
5
Using the formula an= a+(n-1)d you can solve this question.
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