Question 1041255: two numbers are in ratio 4:5. if difference of their cubes is 61, find the number Found 4 solutions by robertb, Edwin McCravy, ikleyn, MathTherapy:Answer by robertb(5830) (Show Source):
Let x = the smaller number
Let y = the larger number
Cross-multiply:
if difference of their cubes is 61,
Substitute for x:
Multiply through by 125
Divide both sides by 61.
Take cube roots of both sides:
Since y = the larger number, the larger number is 5
Since x = the smaller number, and
the smaller number
Edwin
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two numbers are in ratio 4:5. if difference of their cubes is 61, find the number
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= --->
= = .
Let a = , b = .
Then
= (1) and
b - a = 61. (2)
---> a = ---> b - = 61 ---> 125b - 64b = 61*125 ---> 61b = 61*125 ---> b = 125 ---> = 125 ---> y = = 5.
Then x = 4.
Let multiplicative factor be x
Then numbers are: 4x and 5x
Since the difference of their cubes is 61, we can say that: ___________x = 1
Therefore numbers are:
