arithmatic progression..

Asked by deepitapai | 8th Mar, 2009, 04:09: PM

Expert Answer:

Let a be the first term.

sum of nine terms =75(given)

sum of n terms = n/2[2a+(n-1)d]

So,putting n=9 ,d=5, we get,

9/2[2a+40]=75

9[a+20]=75

3a+60=25

Solve and get the value of  a

Substitute that value of a and find the nineth term

 using the formula,

 n th term=a+(n-1)d

 

Answered by  | 8th Mar, 2009, 08:05: PM

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