Volume and Surface Area Questions Answers

1. Find the surface area of a 10cm*4cm*3cm brick.
 154 cm square
 156 cm square
 160 cm square
 164 cm square
Answer And Explanation
Answer: Option D
Explanation:
Surface area of a cuboid = 2(lb+bh+hl) cm square
So,
Surface area of a brick = 2(10*4+4*3+3*10) cm square
= 2(82) cm square = 164 cm square 
2. A cistern 6 m long and 4 m wide contains water up to a breadth of 1 m 25 cm. Find the total area of the wet surface.
 42 m sqaure
 49 m sqaure
 52 m sqaure
 64 m sqaure
Answer And Explanation
Answer: Option B
Explanation:
Area of the wet surface =
2[lb+bh+hl]  lb = 2 [bh+hl] + lb
= 2[(4*1.25+6*1.25)]+6*4 = 49 m square 
3. A boat having a length 3 m and breadth 2 m is floating on a lake. The boat sinks by 1 cm when a man gets into it. The mass of the man is :
 50 kg
 60 kg
 70 kg
 80 kg
Answer And Explanation
Answer: Option B
Explanation:
In this type of question, first we will calculate the volume of water displaces then will multiply with the density of water.
Volume of water displaced = 3*2*0.01 = 0.06 m cube
Mass of Man = Volume of water displaced * Density of water
= 0.06 * 1000 = 60 kg 
4. 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 And Explanation
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} 
5. A swimming pool 9 m wide and 12 m long is 1 m deep on the shallow side and 4 m deep on the deeper side. Its volume is:
 260
 262
 270
 272
Answer And Explanation
Answer: Option C
Explanation:
Volume will be length * breadth * height, but in this case two heights are given so we will take average,
\begin{aligned}
Volume = \left(12*9*\left(\frac{1+4}{2}\right)\right)m^3 \\
12*9*2.5 m^3 = 270 m^3
\end{aligned} 
6. 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 And Explanation
Answer: Option A
Explanation:
Edge of cude = 20/4 = 5 cm
Volume = a*a*a = 5*5*5 = 125 cm cube 
7. 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 And Explanation
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}

Rianne Adriano 4 years ago
Yeahh .. Its ReaLLy Interesting :)

GuruDev 4 years ago
this type of simple question does not come in exam...provide quality Question