A rectangle has 20 cm as its length and 200 sq cm as its

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A rectangle has 20 cm as its length and 200 sq cm as its area. If the area is increased by 1¹/₅ time the original area by increase its length only then the perimeter of the rectangle so formed (in cm) is

1. 72
2. 60
3. 64
4. 68

Correct Option: D

l₁ = 20 cm, A₁ = 200 sq cm
∴ b₁ = 200/20 = 10 cm
Now, A₂ = 200 x 6/5 = 240 sq cm
b₂ = 10 cm
∴ l₂ = 240/10 = 24 cm

∴ Perimeter of new rectangle = 2(l₂ + b₂)
= 2(24 + 10) = 2 x 34 = 68 cm