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Question
From the following table, determine if x and y are in direct proportion or not.
| x | 1 | 4 | 9 | 20 |
| y | 1.5 | 6 | 13.5 | 30 |
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Solution
In direct proportion, `x/y = k` ...(Constant)
For table
| x | 1 | 4 | 9 | 20 |
| y | 1.5 | 6 | 13.5 | 30 |
⇒ `x/y = 1/1.5, 4/6, 9/13.5, 20/30`
i.e. `1/1.5, 1/1.5, 1/1.5, 1/1.5`
So, is in direct proportion.
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