Question

The total time taken for the sale of donuts, tacos, and bagels in a food street is as shown. Which of the following dishes shows a proportional relationship?

Tacos
x: Time in minutes	$\frac{3}{2}$	$\frac{1}{2}$
y: Number of items sold	$30$	$10$

• A. Tacos and donuts
  
• B. Tacos
  
• C. None
  
• D. Bagel, tacos, and donuts
  

Answer 1

The correct option is B Tacos


Tacos: $\frac{y}{x}=30÷\frac{3}{2}=\frac{30}{1}\times \frac{2}{3}=20$

$\frac{y}{x}=10÷\frac{1}{2}=\frac{10}{1}\times \frac{2}{1}=20$

In both cases, $\frac{y}{x}=20$.
Constant of proportionality $=20$
It is a proportional relationship.
Bagel:
The graph representing the sale of bagels is a straight line but does not pass through the origin.
It is not a proportional relationship.
Doughnut:
The graph representing the sale of donuts is a straight line but does not pass through the origin.
It is not a proportional relationship.