The length of a rectangle is increased by 10 % and breadth decreased by 10 % Then the area of a new rectangle is:_________?
A. neither increased nor decreased
B. increased by 1 %
C. decreased by 1 %
D. decreased by 10 %
Explanation:
Let original length = l units and original breadth = b units
Then original Area = lb sq. Units
New length = (110/100 l) units = (11 l)/10 units
New breadth = (90/100 b) units = (9 l)/10 units
New area = (11l/10 × 9b/10) sq. Units = 99lb/100 sq. units
Decrease in area = (lb- 99lb/100)sq units = lb/100 sq. units
Decrease in area = (lb/100 × 1/lb ×100) % = 1 %
Decrease by = 1 %