Question

Let x1 = 12, y1 = 15, and y2 = 3. Let y vary inversely with x. Find x2.

Answer 1

We have that an inverse variation in a function is given by:
 $y = k / x$
 We must find the value of the constant k.
 To do this, we substitute the values of x1 = 12, y1 = 15.
 We have then:
 $15 = k / 12$
 Clearing k we have:
 $k = (15) * (12) k = 180$
 Substituting the value of k we have that the inverse variation is:
 $y = 180 / x$
 For y2 = 3 we have:
 $3 = 180 / x2$
 Clearing x2 we have:
 $x2 = 180/3$
 $x2 = 60$
 Answer:
 $x2 = 60$