Example (with steps)1. If y varies directly as x and x = 4 when y = 2. find k
Solution:
`y prop x`
`=>y=k*x`
Now, `x=4" when "y=2`
`=>2=k*4`
`=>k=(2)/(4)`
`=>k=1/2`
Hence, `y=1/2*x`
2. y prop x and x=4 when y=20. find constant
Solution:
`y prop x`
`=>y=k*x`
Now, `x=4" when "y=20`
`=>20=k*4`
`=>k=(20)/(4)`
`=>k=5`
Hence, `y=5*x`
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