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Question
The difference between two positive numbers is 4 and the difference between their cubes is 316.
Find : Their product
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Solution
Given difference between two positive numbers is 4 and difference between their cubes is 316.
Let the positive numbers be a and b
a - b = 4
a3 - b3 = 316
Cubing both sides,
(a - b)3 = 64
a3 - b3 - 3ab(a - b) = 64
Given a3 - b3 = 316
So 316 - 64 = 3ab(4)
252 = 12ab
So ab = 21; product of numbers is 21
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