If x varies inversely with y and x = 6 when y = 10, how do you find y when x = 8?

Question

10903 views around the world

You can reuse this answer
Creative Commons License

Answer 1 · 2018-04-02T01:08:18

Set up an equation $x = \frac{1}{y}$ $x = 1/y$ substitute to find the constant
$x \times y = C$ $x xx y = C$ Then substitute again to find the new y

$x = C ? y$ $x =C?y$

$6 = \frac{C}{10}$ $6 = C/10$ multiply both sides by 10

$6 \times 10 = \frac{C}{10} \times 10$ $6 xx 10 = C/10 xx 10$ This gives

$60 = C .$ $60 = C.$ Now substitute x for 8 in the equation and 60 for C

$8 = \frac{60}{y}$ $8 = 60/ y$ multiply both sides by y

$8 \times y = \frac{60}{y} \times y$ $8 xx y = 60/y xx y$ This gives

$8 y = 60$ $8y = 60$ now divide both sides by 8

$8 \frac{y}{8} = \frac{60}{8}$ $8y/8 = 60/8$ The answer is

$y = 7.5$ $y = 7.5$

As x gets bigger y gets smaller in an inverse relationship.