Question

X is inversely proportional to y, and x = 18 when y = 4. Write an equation relating the two

Answer 1

`xy=72`

Explanation:

If x is inversely porportionaly to y, then for some constant k,

`x = (k)/(y)\\xy=k`

Since y is 4 when x = 18, k is equal to 4*18=72, so the equation is:

`xy=72`