The first term of an AP is 5 and the last term is 45. The sum is 400. Find n and d.
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Answer:
n = 16
d = 8/3
Step-by-step explanation:
Sn = n/2(a+an)
400=n/2(5+45)
400=n/2*50
400x2/50 = n
n=16
Aftr this u put the formula...
Sn= n/2(2a+n-1)d
Hope helps u.........
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