Question

Y varies directly as xy equals 5 when X is 8 how do you find y when X is 9

Answer 1

Given, y varies directly as x

So,

$y=c\cdot x$

Where c is a constant

When y equals 5 when x is 8

So,

$\begin{gathered} 5=c\cdot8 \\ c=\frac{5}{8} \\ \end{gathered}$

So, the relation between y and x

$y=\frac{5}{8}x$

now , when x = 9

Substitute with x to find y

$y=\frac{5}{8}\cdot9=\frac{45}{8}$

So, the answer is option 2. y = 45/8