Prove the following

Question:

If $\alpha, \beta$ are natural numbers such that

$100^{\alpha}-199 \beta=(100)(100)+(99)(101)+(98)(102)+\ldots \ldots+(1)(199)$

then the slope of the line passing through $(\alpha, \beta)$ and origin is :

  1. (1) 540

  2. (2) 550

  3. (3) 530

  4. (4) 510


Correct Option: 2,

Solution:

$S=(100)(100)+(99)(101)+(98)(102) \ldots \ldots .(2)(198)+(1)(199)$

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

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

$\alpha=3 \quad \beta=1650$

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

Leave a comment