Practicing Success

Target Exam

CUET

Subject

General Test

Chapter

Quantitative Reasoning

Topic

Mensuration: 3D

Question:

A solid metallic sphere of radius x cm is melted and then drawn into 126 cones each of radius 3.5 cm and height 3 cm. There is no wastage of material in this process. What is the value of x?

Options:

10.5

7

3.5

21

Correct Answer:

10.5

Explanation:

We know that,

The volume of sphere = \(\frac{4}{3}\)πR3

Volume of cone = \(\frac{1}{3}\)πr2h

We have,

Total number of cones = 126

Radius and Height of cone = 3.5 cm and 3 cm respectively.

According to the question

\(\frac{4}{3}\)πx3 = 126 × \(\frac{1}{3}\) × πr2h

= x3 = \(\frac{126}{4}\) × 3.5 × 3.5 × 3

= x3 = 3 × 3 × 3.5 × 3.5 × 3.5 × 3 = 10.5 cm