Question

The sum of total surface area of two cubes is 1248-centimeter square. If the product of the length of their edges is 96 centimeter square. Find the difference between the length of their edges.

A 6 Correct Answer Incorrect Answer
B 9 Correct Answer Incorrect Answer
C 5 Correct Answer Incorrect Answer
D 4 Correct Answer Incorrect Answer
E 3 Correct Answer Incorrect Answer

Solution

Let the length of the edges of the two cube be ‘a’ centimeter and ‘b’ centimeter respectively. According to question, 6a² + 6b² = 1248 a² + b² = 208 And ab = 96 Using the formula, x² + y² = (x - y)² = 2xy 208 =   (a - b)² +2*96 (a - b)² =  = 208-196 (a - b)²  =16   a-b =  ± 4 The desired difference = 4 cm 

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