A) 10 m
B) 12 m
C) 13 m
D) 15 m
Correct Answer: C
Solution :
If d be the common difference, then \[m={{a}_{4}}-{{a}_{7}}+{{a}_{10}}={{a}_{4}}-{{a}_{7}}+{{a}_{7}}+3d={{a}_{7}}\] \[{{S}_{13}}=\frac{13}{2}[{{a}_{1}}+{{a}_{13}}]=\frac{13}{2}[{{a}_{1}}+{{a}_{7}}+6d]\] \[=\frac{13}{2}[2{{a}_{7}}]=13{{a}_{7}}=13m\]You need to login to perform this action.
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