Question

If the cost of 1 kg of sugar is ₹ 36, then what would be the cost of 3 kg sugar?
[2 marks]

Answer 1

Let the cost of $3$ kg sugar be $x$.

Quantity (in Kg)	$1$	$3$
Cost (in ₹)	$36$	$x$

As the quantity of sugar [Q] is increasing, the cost [C] will also increase.
Hence, it is a case of direct proportions.
$\Rightarrow \frac{Q}{C}=constant$
$\Rightarrow \frac{Q_1}{C_1}=\frac{Q_2}{C_2}$

[1 mark]

$\Rightarrow \frac{1}{36}=\frac{3}{x}$
$\Rightarrow x=3\times 36=$ ₹ $108$

Hence, the cost of $3$ kg sugar is ₹ $108$

[1 mark]