Q5 of 71 Page 62

The length of a rectangle is twice its breadth. The perimeter of the rectangle is 120 cm. Find the length and breadth of this rectangle. Also find its area.

Let the length be

x and breadth by y.


Given, the length of a rectangle is twice its breadth


⇒ x = 2y


⇒ x – 2y = 0 …[1]


and also, perimeter of the rectangle is 120 cm


⇒ 2(x + y) = 120


⇒ 2x + 2y = 120 …[2]


eq[1] + eq[2]


3x = 120


⇒ x = 40


and x = 2y


⇒ y = 20


The area is product of length and breadth


⇒ area = 20×40


⇒ area = 800 cm2


More from this chapter

All 71 →
3

There are some 25 paise coins and some 50 paise coins in a bag. The total number of coins is 140 and the amount in the bag is Rs. 50. Find the number of coins of each value in the bag.

 4

The sum of the digits of two–digit number is 3. The number obtained by interchanging the digits is 9 less than the original number. Find the original number.

 6

An employee deposits certain amount at the rate of 8% per annum and a certain amount at the rate of 6% per annum at simple interest. He earns Rs. 500 as annual interest. If he interchanges the amount at the same rates, he earns Rs. 50 more. Find the amounts deposited by him at different rates.

 1

Solve the following pairs of equations by cross multiplication method:

0.3x + 0.4y = 2.5 and 0.5x — 0.3y = 0.3