**Assertion (A):** Two cubes each of edge length $10$ cm are joined together. The total surface area of newly formed cuboid is $1200$ cm$^2$.

**Reason (R):** Area of each surface of a cube of side $1

Question

**Assertion (A):** Two cubes each of edge length $10$ cm are joined together. The total surface area of newly formed cuboid is $1200$ cm$^2$.

**Reason (R):** Area of each surface of a cube of side $10$ cm is $100$ cm$^2$.

Accepted Answer

Step 1: When two cubes of edge $10$ cm are joined, the cuboid formed has dimensions $20 	imes 10 	imes 10$. TSA $= 2(20 	imes 10 + 10 	imes 10 + 20 	imes 10) = 2(200 + 100 + 200) = 1000$ cm$^2 
eq 1200$ cm$^2$. So A is false. R is true since each face $= 10 	imes 10 = 100$ cm$^2$.

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