Question:
If the list price of a toy is reduced by Rs. 2, a person can buy 2 toys more for Rs. 360. Find the original price of the toy.
Solution:
Let the original list price of the toy be Rs. x .
Then, the number of toys brought for Rs. $360=\frac{360}{x}$
According to question, reduced list price of the toys $=$ Rs. $(x-2)$.
Therefore, the number of toys brought for Rs. $360=\frac{360}{x-2}$
It is given that
$\frac{360}{x-2}-\frac{360}{x}=2$
$\frac{360 x-360(x-2)}{(x-2) x}=2$
$\frac{720}{(x-2) x}=2$
$2\left(x^{2}-2 x\right)=720$
$\left(x^{2}-2 x\right)=360$
$x^{2}-2 x-360=0$
$x^{2}+18 x-20 x-360=0$
$x(x+18)-20(x+18)=0$
$(x+18)(x-20)=0$
Because x cannot be negative.
Thus, $x=20$ is the require solution.
Therefore, the original list price of the toy be $x=$ Rs. 20