Question

(1): The price of a computer is$$Rs.27000$$. The GST charged is $12\mathrm{\%}$. Find the amount to be paid.
(2): Uma purchased a hair dryer for $$Rs.5400$$including $8\mathrm{\%}$GST. Find the price before GST was added.

Answer 1

Hint: (1) Amount to be paid $=Rs.27000+12\mathrm{\%}$of $Rs.27000$. Solve this to get the amount to be paid.
(2) Price before GST was added $=Rs.5400-8\mathrm{\%}$of $Rs.5400$. Calculate this to get the price before GST was added.

Complete step by step answer:
Let us first understand what a GST is and how GST is applied on the price of an item.
Let us see what a GST is.
GST means goods and services tax. It is an indirect tax used on the supply of goods and services. It is a comprehensive, multi-stage, destination-based tax.

Now let us understand how we apply GST.
If a good or service costs $Rs.x$ and the GST rate applicable is $y\mathrm{\%}$, then the net price calculated will be $=x+x\left({\displaystyle \frac{y}{100}}\right)$ $=x+{\displaystyle \frac{xy}{100}}$.

Now let us solve the given problem.
We have given that the price of a computer is$$Rs.27000$$ and the GST charged is $12\mathrm{\%}$. Then we have to find the amount to be paid.
Price of computer $=Rs.27000$
GST charged on the computer $=$ GST rate $\times$ price of computer
$=12\mathrm{\%}\times Rs.27000$
$={\displaystyle \frac{12}{100}}\times Rs.27000$
$=Rs.3240$.

$\therefore$ Total amount to be paid $=$ Price of computer $+$ GST charged on the computer
$\begin{array}{rl}& =Rs.27000+Rs.3240\\ & =Rs.30,240\end{array}$

Hence, total amount of the computer to be paid is $Rs.30,240$.

It is given that GST is included in the price of the hair dryer. So, for finding the price before GST was added, we will take out the GST charged on the price of the hair dryer. Then the remaining amount will be the price of the hair dryer before GST was added.

Let us understand how to find the price before GST was added.
If a good or service is sold at $Rs.z$ and the GST rate applicable is $t\mathrm{\%}$, then the price before GST was added will be $z+z{\displaystyle \frac{t}{100}}=z+{\displaystyle \frac{zt}{100}}$.

Now let us solve the given problem.
We have given that the price of the hair dryer including is $Rs.5400$and GST rate is $8\mathrm{\%}$. Then we have to find the price before GST was added.

Price of hair dryer including GST $=Rs.5400$
GST charged on hair dryer $=8\mathrm{\%}\times$ price of hair dryer
$=8\mathrm{\%}\times Rs.5400$
$={\displaystyle \frac{8}{100}}\times Rs.5400$
$=Rs.432$

$\therefore$ Price of the hair dryer before GST was added $=$ Price of hair dryer including GST - GST charged on hair dryer.
$=Rs.5400-R.432$
$=Rs.4968$

Hence, price of the hair dryer before GST was added is $Rs.4968$.

Note: (1) We can also solve this by this method:
Amount to be paid $={\displaystyle \frac{112}{100}}\times Rs.27000$
$=Rs.30,240$.
(2) We can also solve this problem by this method:
Price of the hair dryer before GST was added $=(100-8)\mathrm{\%}\times Rs.5400$
$={\displaystyle \frac{92}{100}}\times Rs.5400$
$=Rs.4968$.