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Assertion (A) the Outer Surface of a Hemisphere of Radius 7 Cm is to Be Painted. the Total Cost of Painting at Rs 5 per Cm2 is Rs 2300. - Mathematics

Sum

Assertion (A)
The outer surface of a hemisphere of radius 7 cm is to be painted. The total cost of painting at Rs 5 per cm2 is Rs 2300.

Reason (R)
The total surface area of a hemisphere is 3π r2.

  1. Both Assertion (A) and Reason (R) are true and Reason (R) is a correct explanation of Assertion (A).
  2. Both Assertion (A) and Reason (R) are true but Reason (R) is not a correct explanation of Assertion (A).
  3. Assertion (A) is true and Reason (R) is false.
  4. Assertion (A) is false and Reason (R) is true.
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Solution

Assertion (A) is false and Reason (R) is true.
Assertion (A):
Total surface area of the hemisphere =3πr

`= (3xx22/7xx7xx7) "cm"^2`

= 462 cm2

Cost of painting at Rs 5 per cm= Rs (462 × 5)

= Rs 2310

Hence, Assertion (A) is false.

Reason (R): The given statement is true.

  Is there an error in this question or solution?
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APPEARS IN

RS Aggarwal Secondary School Class 10 Maths
Chapter 19 Volume and Surface Area of Solids
Multiple Choice Questions | Q 78 | Page 927
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