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8. Sequences and Series
hard
तीन समांतर श्रेणियों
$3,7,11,15, \ldots \ldots . . . ., 399$,
$2,5,8,11, \ldots \ldots \ldots \ldots . ., 359$ तथा
$2,7,12,17, \ldots \ldots . ., 197$,
के उभ्यनिष्ठ पदों का योग है ____________I
A
$322$
B
$321$
C
$324$
D
$328$
(JEE MAIN-2023)
Solution
$3,7,11,15, \ldots \ldots \ldots \ldots, 399 \quad d_1=4$
$2,5,8,11, \ldots \ldots \ldots \ldots ., 359 \quad d_2=3$
$2,7,12,17, \ldots \ldots ., 197 \quad d_3=5$
$\operatorname{LCM}\left(d_1, d_2, d_3\right)=60$
Common terms are $47, 107, 167$
$Sum =321$
Standard 11
Mathematics