The actual area of a rectangle is 60 Cm^2, but while measuring its length a student
Posted on 23-12-2022
Ques - The actual area of a rectangle is 60 Cm2, but while measuring its length a student decreases it by 20% and the breadth increases by 25%. The percentage error in area, calculated by the student is :
A. 5%
B. 25%
C. Can't determined
D. None of these
Soution - Actual area of rectangle = 60cm²
L×B = 60--------- (1) (area of rectangle = L×B )
Length decreases = 20%
new length = L - 20% of L
= L - 0.2L
= 0.8L cm
Breadth increases = 25%
new breadth = B + 25% of B
= B + 0.25B
= 1.25B cm
new area = new length ×new breadth
new area = 0.8L × 1.25B
new area = 1 LB
According to equation (1) LB = 60
new area = 1 × LB
new area = 1 × 60
new area = 60cm²
new area = actual area
60cm² = 60cm²
Therefore,
There is no change in area .
Hence,
The correct option is (d) none of these.
Thank You