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11112+11116+111112+111120+111130?111 \frac{1}{2}+111 \frac{1}{6}+111 \frac{1}{12}+111 \frac{1}{20}+111 \frac{1}{30} ? का मूल्य क्या है

a

11116111 \frac{1}{6}

b

11156111 \frac{5}{6}

c

55556555 \frac{5}{6}

d

55516555 \frac{1}{6}

Answer : Option C
Explanation :

अभिव्यक्ति

=111+12+111+16+111+112+111+120+=111+\frac{1}{2}+111+\frac{1}{6}+111+\frac{1}{12}+111+\frac{1}{20}+

111+130=5×111+(12+16+112+120+130)111+\frac{1}{30}=5 \times 111+\left(\frac{1}{2}+\frac{1}{6}+\frac{1}{12}+\frac{1}{20}+\frac{1}{30}\right)

=555+(11×2+12×3+13×4+14×5+15×6)=555+=555+\left(\frac{1}{1 \times 2}+\frac{1}{2 \times 3}+\frac{1}{3 \times 4}+\frac{1}{4 \times 5}+\frac{1}{5 \times 6}\right)=555+

(112+1213+1314+1415+1516)\left(1-\frac{1}{2}+\frac{1}{2}-\frac{1}{3}+\frac{1}{3}-\frac{1}{4}+\frac{1}{4}-\frac{1}{5}+\frac{1}{5}-\frac{1}{6}\right)

=555+(116)=55556=555+\left(1-\frac{1}{6}\right)=555 \frac{5}{6}

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