Question

Y is inversely proportional to x . When y = 3 , x = 20 Work out x when y = 12

Answer 1

x = 5 when y = 12

Explanation:

If y is inversely proportional to x, we can say that x1 : x2 = y2 : y1

The order of y2 and y1 respectively are interchanged as y is inversely proportional to x

Now let us simply substitute our known values, and solve for x2;

x1 : x2 = y2 : y1

20 : x2 = 12 : 3

20/x2 = 12/3

12(x2) = 3(20)

12(x2) = 60

x2 = 60/12 = 5