Question

If $x$ varies as $y$, and $x=8$ when $y=15$, find $x$ and $y=10$.

Answer 1

As $x$ varies as $y$ the let,

$x=ky$

where $k$ is a constant, and $x=8$ and $y=15$ satisfies the equation so,

$8=15k$

$k=\frac{8}{15}$

$x=\frac{8}{15}y$

at $y=10$

$x=\frac{8}{15}.10=\frac{16}{3}=5\frac{1}{3}$