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The length of a rectangle is increased by 20% and breadth decreased by 20%. The area of the new rectangle is?
The length of a rectangle is increased by 20% and breadth decreased by 20%. The area of the new rectangle is?
1). decreased by 2%
2). decreased by 4%
3). neither increased nor decreased
4). increased by 4%
1 answers
2 vote
Let,
Original length of the rectangle = L
Original breadth of rectangle = B
∴ Original area = Length × Breadth = L × B
After increasing 20% Length becomes = L + 0.20L = 1.20L
After decreasing 20% Breadth becomes = L – 0.20L = 0.80L
∴ New area becomes = Length × Breadth = 1.20L × 0.80B = 0.96 × L × B
∴ Decrease in area = (L × B) – (0.96 × L × B) = 0.04 × L × B
∴ Percentage decrease
= (Decrease in area/Original area) × 100%
= {(0.04 × L × B)/(L × B)} × 100%
= 4%