MCQ
Assertion and Reason Type
Each question consists of two statements, namely, Assertion (A) and Reason (R). For selecting the correct answer, use the following code:
Assertion (A)
Reason (R)
A hemisphere of radius 7cm is to be painted outside on the surface. The total cost of painting at $₹ 5\ per\ cm^2$  is $₹ 2300.$
The total surface volume of a hemisphere is $3\pi\text{r}^2.$
  • A
    Both Assertion (A) and Reason (R) are true and Reason (R) is a correct explanation of Assertion (A).
  • B
    Both Assertion (A) and Reason (R) are true but Reason (R) is not a correct explanation of Assertion (A).
  • C
    Assertion (A) is true and Reason (R) is false.
  • Assertion (A) is false and Reason (R) is true.

Answer

Correct option: D.
Assertion (A) is false and Reason (R) is true.
Assertion (A) is false and Reason (R) is true.
The total surface area of the hemisphere
$=\pi\text{r}^2+2\pi\text{r}^2$
$=2\pi\text{r}^2$
$=3\times\frac{22}{7}\times7\times7$
$=462\text{cm}^2$
Cost of painting at $Rs. 5\ per\ cm^2 = Rs. (462 \times 5) = Rs. 2310$
So, the Assertion (A) is false.
The Reason (R) is true.

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