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The perimeter of one face of a cube is 20 cm. Its volume will be:

  • \begin{aligned} 125 cm^3 \end{aligned}
  • \begin{aligned} 400 cm^3 \end{aligned}
  • \begin{aligned} 250 cm^3 \end{aligned}
  • \begin{aligned} 625 cm^3 \end{aligned}

Answer: Option A

Explanation:

Edge of cude = 20/4 = 5 cm

Volume = a*a*a = 5*5*5 = 125 cm cube

Similar Questions :

1. How many bricks, each measuring 25cm*11.25cm*6cm, will be needed to build a wall 8m*6m*22.5m

  • 6100
  • 6200
  • 6300
  • 6400

Answer: Option D

Explanation:

To solve this type of question, simply divide the volume of wall with the volume of brick to get the numbers of required bricks
So lets solve this

Number of bricks =
\begin{aligned}
\frac{\text{Volume of wall}}{\text{Volume of 1 brick}} \\
= \frac{800*600*22.5}{25*11.25*6} \\
= 6400
\end{aligned}

2. The cost of the paint is Rs. 36.50 per kg. If 1 kg of paint covers 16 square feet, how much will it cost to paint outside of a cube having 8 feet each side.

  • Rs. 850
  • Rs. 860
  • Rs. 876
  • Rs. 886

Answer: Option C

Explanation:

We will first calculate the Surface area of cube, then we will calculate the quantity of paint required to get answer.
Here we go,

\begin{aligned}
\text{Surface area =}6a^2 \\
= 6 * 8^2 = 384 \text{sq feet} \\
\text{Quantity required =}\frac{384}{16} \\
= 24 kg\\
\text{Cost of painting =} 36.50*24 \\
= Rs. 876
\end{aligned}

3. How many cubes of 10 cm edge can be put in a cubical box of 1 m edge.

  • 10000 cubes
  • 1000 cubes
  • 100 cubes
  • 50 cubes

Answer: Option B

Explanation:

\begin{aligned}
\text{Number of cubes =}\frac{100*100*100}{10*10*10} \\
= 1000
\end{aligned}

Note: 1 m = 100 cm

4. A cylindrical tank of diameter 35 cm is full of water. If 11 litres of water is drawn off, the water level in the tank will drop by:

  • \begin{aligned} 11\frac{3}{7} cm \end{aligned}
  • \begin{aligned} 11\frac{2}{7} cm \end{aligned}
  • \begin{aligned} 11\frac{1}{7} cm\end{aligned}
  • \begin{aligned} 11 cm\end{aligned}

Answer: Option A

Explanation:

Let the drop in the water level be h cm, then,

\begin{aligned}
\text{Volume of cylinder= }\pi r^2h \\
=> \frac{22}{7}*\frac{35}{2}*\frac{35}{2}*h = 11000 \\
=> h = \frac{11000*7*4}{22*35*35}cm\\
= \frac{80}{7}cm\\
= 11\frac{3}{7} cm
\end{aligned}

5. The volume of the largest right circular cone that can be cut out of a cube of edge 7 cm is:

  • \begin{aligned} 79.8 cm^3 \end{aligned}
  • \begin{aligned} 79.4 cm^3 \end{aligned}
  • \begin{aligned} 89.8 cm^3 \end{aligned}
  • \begin{aligned} 89.4 cm^3 \end{aligned}

Answer: Option C

Explanation:

Volume of the largest cone = Volume of the cone with diameter of base 7 and height 7 cm

\begin{aligned}
\text{Volume of cone =}\frac{1}{3}\pi r^2h \\
= \frac{1}{3}*\frac{22}{7}*3.5*3.5*7 \\
= \frac{269.5}{3}cm^3 \\
= 89.8 cm^3
\end{aligned}

Note: radius is taken as 3.5, as diameter is 7 cm

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