Question:
If 18 dolls cost Rs 630, how many dolls can be bought for Rs 455?
Solution:
Let the required number of dolls be x. Then, we have:
| No of dolls | 18 | x |
| Cost of dolls (in rupees) | 630 | 455 |
Clearly, the less the amount of money, the less will be the number of dolls bought.
So, this is a case of direct proportion.
Now, $\frac{18}{630}=\frac{x}{455}$
$\Rightarrow \frac{1}{35}=\frac{x}{455}$
$\Rightarrow x=\frac{455}{35}$
$\Rightarrow x=13$
Therefore, 13 dolls can be bought for Rs 455.