Question

If x varies inversely with y and x = 6 when y = 10, find y when x = 8.

Answer 1

If they vary in an inverse fashion, then you have one as \(\large \times 2\) and one as \(\large \div 2\).

Answer 2

There is a formula for this. It is \[y=\frac{ k }{ x }\]

Answer 3

You solve for k using the x = 6 and y = 10.

Answer 4

Solving for k, \[10=\frac{ k }{6 }\]

Answer 5

That was just n example, though.. Using a constant of proportionality is more efficient :P

Answer 6

k=60

Answer 7

Now use the facts they gave you that x = 8 and k = 60. Solve for y in the same equation.\[y=\frac{ 60 }{ 8 }\]

Answer 8

y = ?

Answer 9

7.5