MEDIUM
10th West Bengal Board
IMPORTANT
Earn 100

The volume of a sphere varies directly as the cube of its radius. Three spheres of radii 3 cm, 4 cm and 5 cm are melted into a new sphere. Find the radius of the new sphere. 
 

Important Questions on Variation

MEDIUM
10th West Bengal Board
IMPORTANT
SCHOOL MATHEMATICS Class 10>Chapter 4 - Variation>EXERCISE 4>Q 18
The volume of a pyramid jointly varies as the area of the base and height. When the area of the base is 60 sq. cm and height 14 cm, the volume 280 c.c.. Find the area of the base of the pyramid when its height is 26 cm and volume is 390 c.c. 
MEDIUM
10th West Bengal Board
IMPORTANT
SCHOOL MATHEMATICS Class 10>Chapter 4 - Variation>EXERCISE 4>Q 19
The volume of a gas varies directly as the absolute temperature and inversely as pressure. When the pressure is 15 units, temperature 260 units, the volume is 200 units. Find the volume when pressure is 18 units and temperature is 390 units? 
MEDIUM
10th West Bengal Board
IMPORTANT
SCHOOL MATHEMATICS Class 10>Chapter 4 - Variation>EXERCISE 4>Q 20
If 3 men can earn ₹225 in 16 days, find by the principle of variation how many men can earn ₹750 in 8 days? 
MEDIUM
10th West Bengal Board
IMPORTANT
SCHOOL MATHEMATICS Class 10>Chapter 4 - Variation>EXERCISE 4>Q 21
15 farmer can plough 18 bighas of land in 5 days. Find by the principle of variation in how many days can 10 farmers plough 12 bighas of land? 
MEDIUM
10th West Bengal Board
IMPORTANT
SCHOOL MATHEMATICS Class 10>Chapter 4 - Variation>EXERCISE 4>Q 21
5 men can plough 10 acres of land in 9 days. Find by the principle of variation in how many days 25 men can plough 30 acres of land? 
 
MEDIUM
10th West Bengal Board
IMPORTANT
SCHOOL MATHEMATICS Class 10>Chapter 4 - Variation>EXERCISE 4>Q 22
The volume of a sphere varies directly as the cube of its radius and the surface of the sphere varies directly as the square of the radius. Show that, the square of the volume of the sphere varies directly as the cube of the surface. 
MEDIUM
10th West Bengal Board
IMPORTANT
SCHOOL MATHEMATICS Class 10>Chapter 4 - Variation>EXERCISE 4>Q 23
The volume of a cone varies jointly as the height and the square of its radius. The ratio of the heights of two cones is 4:5 and the ratio of radii is 3:4, find the ratio of the volumes of two cones. 
 
HARD
10th West Bengal Board
IMPORTANT
SCHOOL MATHEMATICS Class 10>Chapter 4 - Variation>EXERCISE 4>Q 24
To dig a well x metre deep a part of total expense varies directly as x and the other part varies directly as x2. If the expenses of digging wells 10 metres and 20 metres deep be ₹2000 and ₹4800, find the expense of digging a well 25 metres deep.