Maths-
General
Easy
Question
Two solid cylinders with radii 5 cm and 10 cm and lengths of 7 cm and 5 cm respectively are melted and recast into a cylindrical disc of thickness 3 cm, Calculate its radius.
Hint:
We calculate volumes of both solid cylinders and take the sum. Thickness of the disc will act as the height of the disc and from that equation we find the radius.
The correct answer is: The required radius is 15 cm.
Explanations:
Step 1 of 2:
Volume of the cylinder is 
Total volume = 
cm3
Step 2 of 2:
Let the radius of the re-casted cylindrical disc be R .
Thickness of disc = height of disc = 3 cm
Volume of disc = 
, discarding the negative since distance is always positive
Final Answer:
The required radius is 15 cm.
Related Questions to study
Maths-
Find a value for k so that the line through (k, 6) and (4, 2) is perpendicular to the line with equation x + 2y = 2.Application
Find a value for k so that the line through (k, 6) and (4, 2) is perpendicular to the line with equation x + 2y = 2.Application
Maths-General
Maths-
A Cylinder tank has a 75 cm diameter and 1.8 m height. Find the capacity in litres to three significant figures?
A Cylinder tank has a 75 cm diameter and 1.8 m height. Find the capacity in litres to three significant figures?
Maths-General
Maths-
The graph shows the subscription cost to a certain club in town. Write an equation of the Application
line. Explain what the slope and y-intercept mean in this situation. Then find the total
cost for 2 years.
The graph shows the subscription cost to a certain club in town. Write an equation of the Application
line. Explain what the slope and y-intercept mean in this situation. Then find the total
cost for 2 years.
Maths-General
Maths-
Identify the line having slope 2.
Identify the line having slope 2.
Maths-General
Maths-
A Rectangular piece of cardboard with dimensions 6 inches by 8 inches is used to make the curved side of a cylinder-shaped container. Using this cardboard What is the greatest volume of the cylinder can hold?
A Rectangular piece of cardboard with dimensions 6 inches by 8 inches is used to make the curved side of a cylinder-shaped container. Using this cardboard What is the greatest volume of the cylinder can hold?
Maths-General
Maths-
A certain population of bacteria had an initial population of 1500. It then started growing at a rate of 2000 per day. Write the Application equation to model this situation. What are the slope and y-intercept? Explain.
A certain population of bacteria had an initial population of 1500. It then started growing at a rate of 2000 per day. Write the Application equation to model this situation. What are the slope and y-intercept? Explain.
Maths-General
Maths-
Find equation of a line parallel to line with an equation y = 5x + 1 and passing through (1, 10).
Find equation of a line parallel to line with an equation y = 5x + 1 and passing through (1, 10).
Maths-General
Maths-
A mango candy costs $5 and a strawberry candy costs $3. Alex wants to buy both types of candies and he has $40 with him .Application Write an equation in standard form Ax + By = C that models this situation. What do the values of A, B, and C mean in this situation?
A mango candy costs $5 and a strawberry candy costs $3. Alex wants to buy both types of candies and he has $40 with him .Application Write an equation in standard form Ax + By = C that models this situation. What do the values of A, B, and C mean in this situation?
Maths-General
Maths-
If the equation of a line is 2x – 3y = 6, find its slope and y-intercept.
If the equation of a line is 2x – 3y = 6, find its slope and y-intercept.
Maths-General
Maths-
You can rent books at a local store for $5.00 each. An Internet company offers a flat fee of $20.00 per month for as many books as you want. How many books do you need to rent to make the online rental a better buy?
You can rent books at a local store for $5.00 each. An Internet company offers a flat fee of $20.00 per month for as many books as you want. How many books do you need to rent to make the online rental a better buy?
Maths-General
Maths-
An insulated collar is made to cover a pipe. Find the volume of the material used to make the collar. Let r=3 inches, R=5 inches and h= 21 inches.
An insulated collar is made to cover a pipe. Find the volume of the material used to make the collar. Let r=3 inches, R=5 inches and h= 21 inches.
Maths-General
Maths-
Find the slope and write the equation of the given line.
Find the slope and write the equation of the given line.
Maths-General
Maths-
Find the value of p so that
Find the value of p so that
Maths-General
Maths-
The diameter of a cylinder is 7 yards. The height is 12 yards. What is the volume in terms of π and to the nearest cubic yard of the cylinder?
The diameter of a cylinder is 7 yards. The height is 12 yards. What is the volume in terms of π and to the nearest cubic yard of the cylinder?
Maths-General
Maths-
Which of the following lines pass through origin?
Which of the following lines pass through origin?
Maths-General
