How many terms of the series 54, 51, 48,.........must be taken so that their sum is 513?
Explain the double answer.
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Answer:18, 19
Step-by-step explanation:
= 54 d = -3
Sn = 513
Sn = n/2(2a + (n-1)d)
513 = n/2( 108 + 3-3n)
1026 = 111 n- 3n^2 =
n^2-37n +342 = 0
on solving, we get n= 18, n=19
We are getting here 2 values, both positive so, Both are applicable here.
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