SSC Selection Post 2024 PYQ — Question 67

The correct answer is option 1 i.e. 59%.

Surface area of a cube = 6a² = 5400

a² = 5400/6 = 900

⇒ a = $\sqrt{900}$ = 30 units

Original volume = V₁ = a³ = 30³ = 27000 units³

New side = a + 5 = 35

New volume = V₂ = 35³ = 42875 units³   

Increase = 42875 − 27000 = 15875 units³ 

Approximate increase in volume = 0.59 × 27000

⇒ 15870 cubic units

The volume would increase approximately 59% .