Question

The value of y varies directly with x. When y= 3 3/4 , x = 3/4what’s the value of y when x is 1/2

Answer 1

Step 1:

Write the equation connecting y and x.

`\begin{gathered} y\text{ }\alpha\text{ x} \\ y\text{ = kx where k is constant.} \end{gathered}`

Step 2:

Use the values of y and x to find the constant k.

`\begin{gathered} y\text{ = 3}(3)/(4)\text{ and x = }(3)/(4) \\ y\text{ = kx} \\ \text{Substitute y and x.} \\ 3(3)/(4)\text{ = }(3)/(4)k \\ (15)/(4)\text{ = }(3)/(4)k \\ \text{Cancel 4 at both sides.} \\ 15\text{ = 3k} \\ k\text{ = }(15)/(3) \\ k\text{ = 5} \end{gathered}`

Final answer

Find y when x = 1/2

`\begin{gathered} y\text{ = kx} \\ y\text{ = 5x} \\ y\text{ = 5}*\text{ }(1)/(2) \\ y\text{ = }(5)/(2)\text{ or 2}(1)/(2) \end{gathered}`