All Exams Test series for 1 year @ ₹349 only
Question

A rectangle becomes a square when its length and breadth are reduced by 10 m and 5 m, respectively. During this process, the rectangle loses 650 m² of area. What is the area of the original rectangle in square meters?

The correct answer is
2250

Rectangle Reduction Scenario

We are given a rectangle. When its length is decreased by 10 m and its breadth by 5 m, it transforms into a square. This transformation also results in a loss of 650 m² from the original area.

Equations from Conditions

Let the original length of the rectangle be $L$ meters and the original breadth be $B$ meters.

The original area of the rectangle is $A_{orig} = L \times B$. After the reductions, the new length is $L-10$ and the new breadth is $B-5$. Since the new shape is a square, its sides must be equal:

$ L - 10 = B - 5 \quad (1) $

The new area is $A_{new} = (L-10)(B-5)$. The problem states that the area loss is 650 m²:

$ A_{orig} - A_{new} = 650 $ $ (L \times B) - (L-10)(B-5) = 650 \quad (2) $

Dimensions Solved

We solve the system of equations to find the original dimensions:

  1. From equation (1), we express $L$ in terms of $B$: $ L = B - 5 + 10 $ $ L = B + 5 $
  2. Substitute this expression for $L$ into equation (2): $ ((B+5) \times B) - ((B+5-10) \times (B-5)) = 650 $ $ (B^2 + 5B) - ((B-5) \times (B-5)) = 650 $
  3. Expand and simplify the equation: $ (B^2 + 5B) - (B^2 - 10B + 25) = 650 $ $ B^2 + 5B - B^2 + 10B - 25 = 650 $ $ 15B - 25 = 650 $
  4. Solve for $B$: $ 15B = 650 + 25 $ $ 15B = 675 $ $ B = \frac{675}{15} $ $ B = 45 \text{ m} $
  5. Calculate $L$ using $L = B + 5$: $ L = 45 + 5 $ $ L = 50 \text{ m} $

Original Area Calculation

Now, calculate the area of the original rectangle using the found dimensions $L=50$ m and $B=45$ m:

$ \text{Original Area} = L \times B $ $ \text{Original Area} = 50 \text{ m} \times 45 \text{ m} $ $ \text{Original Area} = 2250 \text{ m}^2 $

Was this answer helpful?

Important Questions from Mensuration and Geometry

  1. In the given figure, $P, Q$, and $R$ are three points on a circle of radius 10 cm with $O$ as its center, $\overline{PQ} = \overline{RQ}$, and $\angle PQR = 45^\circ$. The figure is representative.
    The area of the shaded region $PQRO$ is ______________ cm$^2$.

  2. A straight line $y = x - 1$ intersects a circle with center at $x = 1, y = 1$ and radius of magnitude 1 at two points. The length of the chord formed by this intersection is _______. (rounded off to three decimal places)
  3. The shell of a hollow spherical nanoparticle has a uniform thickness of 3 nanometers (nm). The outer radius of the nanoparticle is 5 nm. The ratio of the volume of the shell to the volume of the hollow core is ________
    (Round off to one decimal place)
  4. The volume of a sphere of diameter 1 unit is ______ than the volume of a cube of side 1 unit.
  5. A window is made up of a square portion and an equilateral triangle portion above it. The base of the triangular portion coincides with the upper side of the square. If the perimeter of the window is 6 m, the area of the window in $m^2$ is ______
Need Expert Advice?

Start Your Preparation with Prepp Mobile App

Download the app from Google Play & App Store
Download the app from Google Play & App Store
Prepp Mobile App