Question

$\text{If 3 kg of sugar contains}9\times {10}^8\text{crystals. How many sugar crystals are there in 4 kg of sugar?}$

Answer 1

Let the required number of crrystals be x.

Surgar (in kg)	3	4
Number of crystals	$9\times {10}^8$	x

Since the two quantities are directly proportional to each other.

$\therefore \frac{x_1}{y_1}=\frac{x_2}{y_2}$

$\Rightarrow \frac{3}{9\times {10}^8}=\frac{4}{x}$

$\Rightarrow 3\times x=4\times 9\times {10}^8$

$\therefore x=\frac{4\times 9\times {10}^8}{3}$

$=12\times {10}^8=1.2\times {10}^9$

$\text{Hence, the required number of crystals}=1.2\times {10}^9.$