The area of a rectangle gets reduced by 80 sq units, if its length is reduced by 5 units and
breadth is increased by 2 units. If we increase the length by 10 units and decrease the
breadth by 5 units then the area will be increased by 50 sq units. Find the length and
breadth of the rectangle.
Answers
Answer:
Let length and Breadth be l,b
and the Area be A=l∗b.............(1)
Now, According to Question
A−80=(l−5)(b+2)⇒A−80=lb+2l−5b−10⇒2l−5b=−70................(2) (Since, A=l*b)
Similarly,
A+50=(l+10)(b−5)⇒A+50=lb−5l+10b−50⇒10b−5l=100..............(3)
Solving (2) and (3)
we get, l=40,b=30
Step-by-step explanation:
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- Length of the rectangle = 40 unit .
- Breadth of rectangle = 30 unit .
Step-by-step explanation:
Given :-
- The area of a rectangle gets reduced by 80 sq units, if its length is reduced by 5 units and breadth is increased by 2 units.
- If we increase the length by 10 units and decrease thebreadth by 5 units then the area will be increased by 50 sq units.
To find :-
★ Find the Length and Breadth of the Rectangle .
Formula used :-
Area of Rectangle = Length × Breadth .
Solution :-
- Let Length of rectangle = x unit .
- Let Breadth of rectangle = y unit .
So,
Area of Rectangle = ( x × y ) unit²
= xy unit² .
Now,
A.T.Q.
The area of a rectangle gets reduced by 80 sq units, if its length is reduced by 5 units and
breadth is increased by 2 units.
So,
( x – 5 ) ( y + 2 ) = xy – 80
xy + 2x – 5y – 10 = xy – 80
xy – xy + 2x – 5y = – 80 + 10
2x – 5y = –70 .........eq.(1)
Now,
If we increase the length by 10 units and decrease the breadth by 5 units then the area will be increased by 50 sq units.
So,
( x + 10 ) ( y – 5 ) = xy + 50
xy – 5x + 10y –50 = xy + 50
xy – xy –5x + 10y = 50 + 50
–5x + 10y = 100 ............eq.(2)
Multiply by 2 in eq.(1) we get --
4x –10y = –140 ...........eq.(3)
Add eq.(2) and eq.(3) we get --
–5x + 10y = 100
4x –10y = –140
– x = – 40
x = 40
Put the value of x = 40 in eq.(2) we get --
⟼ –5x + 10y = 100
⟼ –5 × 40 + 10y = 100
⟼ –200 + 10y = 100
⟼ 10y = 100 + 200
⟼ 10y = 300
⟼ y = 300/10
⟼ y = 30
So,
Length of the rectangle = x = 40 unit
Breadth of the rectangle = y = 30 unit