Page 260 - Math_Genius_V1.0_C8_Flipbook

E:\Working\Focus_Learning\Math_Genius-8\Open_Files\13_Chapter_10\Chapter_10
\ 06-Jan-2025 Bharat Arora Proof-7 Reader’s Sign _______________________ Date __________

6. Below are the drawings of cross sections of two different pipes used to fill swimming pools. Figure A
is a combination of 2 pipes, each having a radius of 8 cm. Figure B is a pipe having a radius of
15 cm. If the force of the flow of water coming out of the pipes is the same in both the cases, which
will fill the swimming pool faster?

8 cm 8 cm 15 cm

Figure A

Figure B
7. Find the area of the following fields. All dimensions are in metres.

(a) D (b) B
D
40
100 C 30
M 10 10 10 L
A 20 E
F 100 C 20 I 30 J 40 K
30 20
80 50 F
H

E 120 G G
30 H 50 B

50
A
8. From a pipe of an inner radius 0.75 cm, water flows at the rate of 7 m per second. Find the volume

(in litres) of water delivered by the pipe in 1 hour. CompetenCy Based Question

Mental Maths
1. A cubical pit of side length 6 m is dug in a field and soil is taken out. Find the surface area of
the pit.
2. If the volume of two cubes are in the ratio 27 : 8, find the ratio of their sides.
3. Find the percentage increase in the volume of a cube if its edge is doubled.
4. Find the percentage decrease in the area of a square if its side length is halved.

258