SOLUTION: Rectangle of a perimeter is 240cm. If the lenght of rectangle is decreased by 10% & breadth is increased by 20% the perimeter remain same(i.e. 240cm) find the length & breadth of r

Algebra.Com
Question 103946: Rectangle of a perimeter is 240cm. If the lenght of rectangle is decreased by 10% & breadth is increased by 20% the perimeter remain same(i.e. 240cm) find the length & breadth of rectangle
Answer by ankor@dixie-net.com(22740)   (Show Source): You can put this solution on YOUR website!
Rectangle of a perimeter is 240cm. If the length of rectangle is decreased by 10% & breadth is increased by 20% the perimeter remain same(i.e. 240cm) find the length & breadth of rectangle
:
"Rectangle of a perimeter is 240cm."
:
Let x = the original length; y = original width
:
2x + 2y = 240
Simplify divide equation by 2:
x + y = 120
or
y = (120-x); for substitution
:
"If the lenght of rectangle is decreased by 10% & breadth is increased by 20% the perimeter remain same(i.e. 240cm)"
New length = .9x
New width = 1.2y
:
2(.9x) + 2(1.2y) = 240
Simplify, divide by 2
.9x + 1.2y = 120
:
"find the length & breadth of rectangle"
:
Substitute(120-x) for y in the above equation, find x:
.9x + 1.2(120-x) = 120
.9x + 144 - 1.2x = 120
.9x - 1.2x = 120 - 144
-.3x = -24
x = -24/-.3
x = + 80 cm is the original length
:
Width: 120 - 80 = 40 cm is the original width
:
Find the new dimension:
.9 * 80 = 72 cm, new length
1.2 * 40 = 48 cm new width
:
Check the new perimeter
2(72) + 2(48) =
144 + 96 = 240

RELATED QUESTIONS

the perimeter of a rectangle is 240cm . if the lenght is decreased .if the lenght is... (answered by ankor@dixie-net.com)
The perimeter of rectangle is 240cm if it's length decreased by 1o% and the breadth is... (answered by ikleyn)
the perimeter of rectangle 240 cm. its length is decreased by 10% & its breadth increased (answered by ankor@dixie-net.com)
If lenght of a rectangle is increased by 30% and the width is decreased by 20% then by... (answered by KMST)
a rectangle has a lenght which is 5cm less than twice its breadth. if the length is... (answered by Cromlix)
If the length of the rectangle is exceeds its breadth by 7cm and the length is decreased... (answered by josgarithmetic)
the perimeter of a rectangle is 26cm.The area of the rectangle remains unaltered if the... (answered by ankor@dixie-net.com)
The length of a rectangle exceeds its breadth by 7 ems. If the length is decreased by 4... (answered by josgarithmetic)
Length of a rectangle is 5 cm less then twice its breadth, if the length is decreased by... (answered by ankor@dixie-net.com)