The sum of the series 1, 5, 9, 13 _______ to 40th series is:
- 154
- 314
- 3160
- 158
- None of these
Explanation
1,5,9,13, ---- 40th
d=5-1=4 d=9-5=4 =1+(40-1)*4 =1+156 =157
U have to use the formula S=n/2 [2a+(n-1)d]
S=40/2[2(1)+(40-1)4]
S=20[2+(39)4]
S=20[156]
S=3160
ND-8-08-2023
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