Question

The variables y and x have a proportional relationship, and y = 15 when x = 3. What is the value of x when y = 4?

Answer 1

The answer is 0.8

Explanation:

divide 15 / 3 = 5

then divide 4 / 0.8 that equals 5

Answer 2

`x=(4)/(5)=0.8`

Explanation:

We have been given that the variables y and x have a proportional relationship, therefore, we can represent the relationship between x and y as:
`y=kx`, where k is proportionality constant.

Let us substitute x=3 and y=15 in above equation to find the value of k.

`15=k*3`

`k=(15)/(3)`

`k=5`

Now let us substitute k=5 and y=4 in our proportionality equation to find the corresponding value of x.

`4=5x`

`x=(4)/(5)`

`x=0.8`

Therefore, the value of x will be 0.8, when y equals to 4.