If each edge of a cube is increased in increased by 50%,

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If each edge of a cube is increased in increased by 50%, the percentage increase in surface area is ?

1. 50 %
2. 75 %
3. 100 %
4. 125 %

Correct Option: D

Let original length of cube = L
Then, its surface area = 6L²
New edge = (150 x L)/10 = 3L/2
New surface area = 6 x (3L/2)² = (6 x 9 x L²)/4 = (27/2) x L²
Increase in surface area = (27/2 - 6) x L² = 15 x L²/2
∴ Increase percent = (15 x L²/2 ) / (6L²) x 100 % = 125 %