Question

Quantity is directly proportional to price, then find the constant of proportionality.

Quantity	3	5	7	9	11
Price	150	250	350	450	550

• A. $\frac{1}{51}$
• B. $\frac{1}{50}$
• C. $\frac{2}{99}$
• D. $\frac{1}{25}$

Answer 1

The correct option is B $\frac{1}{50}$

Given that quantity is directly proportional to price.

If $y$ and $x$ are in direct proportion, then $y=kx$.
Here, $y=$ quantity and $x=$ price and $k=$ constant of proportionality.
$k=\frac{y}{x}$
$k=\frac{3}{150}=\frac{5}{250}=\frac{7}{350}=\frac{9}{450}=\frac{11}{550}=\frac{1}{50}$

$⟹k=\frac{1}{50}$