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Question
The mass of an aluminum rod varies directly with its length. If a 16 cm long rod has a mass of 192 g, find the length of the rod whose mass is 105 g.
Solution
According to the question, the mass (m) of an aluminium rod varies directly with its length (l).
Here, we use the direct proportion.
In diret proportion, `m/l = k` ...(Constant)
∴ `m/l = 192/16 = 12`
⇒ k = 12
If mass of the rod = 105 g
Then, `m/l = k`
⇒ `105/l = 12`
⇒ `l = 105/12 = 8.75 cm`
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