Question

During a sale, a shop offered a discount of 10% on the market prices of all the items. What would a customer have to pay for a pair of jeans marked at Rs.1450 and two shirts marked at Rs.850 each?

Answer 1

Hint: Here, we need to calculate how much is the value of 10% in 1450 and 850 by using the respective formula and then multiply each of them by 2 and then add to get the final result.
\[\dfrac{x}{100}\times y\]

Equation: A statement of equality of two algebraic expressions involving two or more unknown variables is called equation.

Linear Equation: An equation involving the variables in maximum of order 1 is called a linear equation. Graph of a linear equation is a straight line.

Linear equation in one variable is of the form \[ax+b=0\].

Linear equation in two variables is of the form \[ax+by+c=0\] .

Complete step-by-step answer:
Now, let us look at the percentage formula.

The value of x% in y can be written as:

\[\dfrac{x}{100}\times y\]

 Now, on comparing for the case of jeans we get,

\[x=10,y=1450\]

\[\begin{align}
  & \Rightarrow \dfrac{x}{100}\times y \\
 & \Rightarrow \dfrac{10}{100}\times 1450 \\
 & \Rightarrow \dfrac{10}{10}\times 145 \\
 & \Rightarrow 1\times 145 \\
 & \Rightarrow Rs.145 \\
\end{align}\]

Let us assume the cost of each jeans after the discount as J.

\[\begin{align}
  & \Rightarrow J=1450-145 \\
 & \therefore J=Rs.1305 \\
\end{align}\]

Now, let us consider the shirts and on comparing we get,

\[x=10,y=850\]

\[\begin{align}

  & \Rightarrow \dfrac{x}{100}\times y \\

 & \Rightarrow \dfrac{10}{100}\times 850 \\

 & \Rightarrow \dfrac{10}{10}\times 85 \\

 & \Rightarrow 1\times 85 \\

 & \Rightarrow Rs.85 \\

\end{align}\]

Now, let us assume that the cost of each shirt after discount as S.

\[\begin{align}
  & \Rightarrow S=850-85 \\
 & \therefore S=Rs.765 \\
\end{align}\]

Let us assume that the amount to be paid by the customer as A

\[\begin{align}
  & \Rightarrow A=2\left( J+S \right) \\
 & \Rightarrow A=2\left( 1305+765 \right) \\
 & \Rightarrow A=2\left( 2070 \right) \\
 & \therefore A=Rs.4140 \\
\end{align}\]

Hence, the customer has to pay Rs.4140 after the discount.

Note: Instead of assuming various variables to calculate the cost of each jeans and shirt after discount we can directly calculate it for a pair of them by multiplying it with 2 and then subtracting the percentage value calculated according to the discount to be given and then add them there itself. Both methods give the same result.
Here, we need to subtract the value of the percentage from the given total value because we were given a discount which means the reduced cost of the good we are going to purchase. Then when calculating the total amount to be paid we multiplied it with two because the given cost and discount are for each particular good and as here the customer is buying a pair of them. So, we need to multiply it with 2.