Question

If a sheet measuring 1 m² costs ₹ 20, then the cost of the sheet required for making a cubical stand of edge 2.5 m, which is open from the top, is _______ .

• A. ₹ 600
• B. ₹ 625
• C. ₹ 655
• D. ₹ 675

Answer 1

The correct option is B ₹ 625

Given, edge length of the cubical stand, which is open from the top, is 2.5 m.
The surface area of the stand = lateral surface area of cube + base area
We know, curved surface area of cube = 4(edge)${}^2$
$\therefore$ The surface area of the cubical stand
$=(4\times {2.5}^2)+(2.5\times 2.5)=25+6.25=31.25m^2$
Given, the cost of 1 m${}^2$ of the sheet is ₹ 20.
The total cost for making the cubical stand
$=\text{Total area}\times {\text{cost for 1 m}}^2\text{of the sheet}$
$=31.25\times 20$
$=₹625$