Question

If the cost of $65$ tea-packets of the same size is Rs.$2600$, what is the cost of $75$ such packets?

Answer 1

We know if the number of tea packets purchased increases then the cost also increases. Therefore, cost of tea-packets directly varies with the number of tea packets

No. of tea packets (x)	$65$	$75$
Cost (y)	$2600$	?

So $\frac{x_1}{y_1}=\frac{x_2}{y_2}$ Here $x_1=65$ $y_1=2600$ $x_2=75$ $y_2=?$
By substituting $\frac{65}{2600}=\frac{75}{y_2}$ $\Rightarrow$ $y_2=\frac{75\times 2600}{65}=$ Rs.$3000$
So cost of $75$ such packets is Rs.$3000$