Question

The y-intercept of the line plotted in the above graph is units.

• A. 54
• B. 64
• C. 74

Answer 1

The correct option is A 54

From the graph consider the points $(10,74)$ and $(30,114)$

You know,
Slope (m) = $\frac{y_2-y_1}{x_2-x_1}$

Putting values, you get,
Slope (m) $=\frac{114-74}{30-10}$
$=\frac{40}{20}$
$=2$

The equation of a stright line is: $y=mx+c$ (where c is the y-intercept)

∴ Subtituting for the value of m, you have,
$y=2x+c$

Consider the given point $(10,74)$ and put the respective value in the equation $y=2x+c$.

So, $74=2\times 10+c$
$\Rightarrow 74=20+c$
$\Rightarrow c=74-20$
$\Rightarrow c=54$

∴ Value of y-intercept of the graph is 54 units.