n-similar balls each of weight w when weighed in pairs the sum of the weights of all the possible pairs is 120 when they are weighed in triplets the sum of the weights comes out to be 480 for all possible triplets,then n is:

Explanation

Weight of a pair of balls ` = 2w`

Weight of triplets of balls `= 3w`

Number of possible pairs ` = C(n,2)`

Number of possible triplets ` = C(n,3)`

Now, we are given,
`C(n,2)**2w = 120->(1)`

`C(n,3)**3w = 480->(2)`

Dividing `(1)` by `(2)`,

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