# Ex.8.3 Q6 Compairing Quantities - NCERT Maths Class 7

## Question

Juhi sells a washing machine for \(\rm Rs\, 13,500.\) She loses \(20\%\) in the bargain. What was the price at which she bought it?

## Text Solution

**What is Known?**

Price at which Juhi sold the washing machine \(\rm (Rs \,13,500)\) and loss she made \((20\%).\)

**What is Unknown?**

The price at which Juhi bought the washing machine.

**Reasoning:**

This question can be solved by assuming the cost price of the washing machine as \(\rm Rs\, 100.\) Since loss is \(20\%,\) the selling price will be \(\rm Rs \,80.\) Now a simple logic can be used. If selling price is \(\rm Rs\, 80\) then cost price is \(\rm Rs\, 100.\) What will be the cost price if seeling price is \(\rm Rs \,13500.\)

**Steps:**

Let us assume cost of washing machine \(= \rm Rs\, 100\)

Loss \(= 20\%\) of cost price

So, the selling price will be

\[\begin{align}&= \text{Cost price - loss}\\&= 100\,{\rm{- 20}}\\&= \rm{Rs}\,{\rm{80}}\end{align}\]

If selling price is \(\rm Rs \,80,\) the cost price \(= \rm Rs \,100\)

If selling price is Rs \(13,500\) the cost price

\[\begin{align}&= \frac{{{\rm{100}}}}{{{\rm{80}}}} \times{\rm{13500}}\\ &= \,{\rm{Rs}}\,{\rm{16875}}\end{align}\]