Question

The linear equation representing the relation between number of items (x) and their weight (y) is ____.

• A. x = y
• B. x = 15y
• C. y = 15x
• D. y = 30x

Answer 1

The correct option is C y = 15x

The table shows that weight of 3 items is 45 kg and cost of 7 articles is 105 kg.

$\because \frac{45}{3}=\frac{105}{7}=15$

$\therefore$ The number of items and their weight are in proportion.

Slope for the above table is:
$m=\frac{\text{Rise}}{\text{Run}}=\frac{105-45}{7-3}=\frac{60}{4}=15$

$\because$ The equation of line representing proportionality relation is y = mx, where m is slope, the required equation is y = 15x.