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The volume of a cuboid is 5a2 - 80b2. Which of the options below can be possible dimensions of the cuboid?
Question

The volume of a cuboid is 5a2 - 80b2. Which of the options below can be possible dimensions of the cuboid?

A.

5, 2a-b, 2a+b

B.

5, a-4b, a+4b

C.

5, a-b, a+4b

D.

5, 2a-b, a+2b

Correct option is B

Given :

The volume of the cuboid(V) = 5a2^2-80b2^2 

Formula Used: 

​The volume of the cuboid;

V = Length × Breadth × Height  

Solution: 

Analyzing the each option :

Option (a): 5 , 2a−b , 2a+b

The volume would be:

V=5 × ( 2a − b ) × ( 2a + b )

V = 5 × ( 4a2^2 − b2^2 ) = 20a2^2 − 5b2^2

So, option (a) is not correct.

Option (b): 5 , a−4b , a + 4b

The volume would be:

V = 5 × ( a − 4b ) × ( a + 4b )

V = 5 × ( a2^2 − 16b2^2 ) = 5a2^2 − 80b2^2

This is equal to 5a280b25a^2 - 80b^2

So, option (b) is correct

Option (c): 5 , a−b , a+4b

V=5 × ( a − b ) × ( a + 4b )

V=5×(a2+3ab4b2)V = 5 \times (a^2 + 3ab - 4b^2)​​

So option (c) is not correct.

Option (d): 5 , 2a−b , a+2b

The volume would be:

V = 5 × ( 2a − b ) × ( a + 2b )

V = 5 × ( 2a2^2 + 3ab − 2b2^2 ) =10a2^2​+15ab − 10b2^2

So option (d) is not correct.

The, possible dimensions of the cuboid : 5 , a−4b , a + 4b

Hence, Option (b) is correct answer

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