Question

In which equation is the constant of proportionality 5?

A. x=5y

B. y=5x

C. y= x+5

D. y=5-x

Answer 1

The constant or proportionality is in the equation:
y = kx

Where 'k' is the constant of variation or the proportionality.

y = 5x would demonstrate this.

Answer: B. y=5x

Answer 2

Answer: B. y=5x

Explanation:

We know that the rate of change which is also known as the constant of proportionality (
`c=(y)/(x)`) which is the constant ratio between two proportional quantities .

Let's find constant of proportionality in all of the given options:

A. x=5y

`\Rightarrow\ (y)/(x)=(1)/(5)\\eq5`

B.y=5x

`\Rightarrow\ (y)/(x)=5`

C. y=x+5

`\Rightarrow\ (y)/(x)=(x+5)/(x)\\eq\text{constant of proportionality}`

D.y=5-x

`\Rightarrow\ (y)/(x)=(5-x)/(x)\\eq\text{constant of proportionality}`

Thus, in B the constant of proportionality is 5.