The number of straight lines that can be form | vedclass

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(D) To form a straight line,we need $2$ points. If no three points were collinear,the total number of lines would be $^{20}C_2$. However,$4$ points ar

Vedclass · Accepted Answer

$185$

Vedclass · Answer

(D) To form a straight line,we need $2$ points. If no three points were collinear,the total number of lines would be $^{20}C_2$. However,$4$ points are collinear,which means they form only $1$ line instead of $^{4}C_2$ lines. Therefore,the number of lines is given by the formula: $^{20}C_2 - ^{4}C_2 + 1$. Calculating the values: $^{20}C_2 = \frac{20 	imes 19}{2} = 190$. $^{4}C_2 = \frac{4 	imes 3}{2} = 6$. Required number of lines $= 190 - 6 + 1 = 185$.

The number of straight lines that can be formed by joining $20$ points,no three of which are in the same straight line,except $4$ of them which are in the same line.

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