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Let S(k) = (1+2+3+...+k)/(k). If S(1)^(2...

Let `S_(k) = (1+2+3+...+k)/(k)`. If `S_(1)^(2) + s_(2)^(2) +...+S_(10)^(2) = (5)/(12)A`, then A is equal to

A

156

B

283

C

303

D

301

Text Solution

Verified by Experts

The correct Answer is:
C
Given `S_(k)=(1+2+3+……+k)/(k)=(k(k+1))/(2k)=(k+1)/(2)`
`sum_(k=1)^(10)S_(1)^(2)=sum_(k=1)^(10)((k+1)/(2))^2=(5)/(12)ArArr (2^2+3^2+.....+11^2)/(4)=(5)/(12)A`
`A=303`
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