Question

If y varies inversely as x and y= 2/5 when x= 2, find y when x= 1

Answer 1

Answer:

y = 4/5

Step-by-step explanation:

Since, y varies inversely as x.

$\therefore \: y = \frac{k}{x} \\ (k = constant \: of \: proportionality) \\ \therefore \: xy = k...(1) \\ plug \: y = \frac{2}{5} \: and \: x = 2 \: in \: (1) \\ 2\times \frac{2}{5} = k \\ \implies \: k = \frac{4}{5} \\ substituting \: k= \frac{4}{5} \: in \: (1) \\ xy = \frac{4}{5} ..(2) \\ this \: i s \: the \: equation \: of \: variation \\ plug \: x = 1 \: in \: (2) \\ 1 \times y = \frac{4}{5} \\ \huge \red{ \boxed{y = \frac{4}{5} }}$