Solve this following

Question:

If $\alpha, \beta$ are natural numbers such that $100^{\alpha}-199 \beta=(100)(100)+(99)(101)+(98)(102)$ $+\ldots . .+(1)(199)$, then the slope of the line passing through $(\alpha, \beta)$ and origin is :

 

  1. 540

  2. 550

  3. 530

  4. 510


Correct Option: , 2

Solution:

$S=(100)(100)+(99)(101)+(98)(102) \ldots . .$

$\ldots(2)(198)+(1)(199)$

$S=\sum_{x=0}^{99}(100-x)(100+x)=\sum 100^{2}-x^{2}$

$=100^{3}-\frac{99 \times 100 \times 199}{6}$

$\alpha=3$

$\beta=1650$

slope $=\frac{1650}{3}=550$

 

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