Question

he variable z is directly proportional to x, and inversely proportional to y. When x is 7 and y is 7, z has the value 2. What is the value of z when x=10, and y=12?

Answer 1

`z \alpha (x)/(y)`

`z = (kx)/(y)`
Case 1:
But, x=7, y=7 and z=2
From;

`z = (kx)/(y)`

`2 = (k7)/(7)`

`2 * 7 = 7k`

`14 = 7k`

`k = (14)/(7)`

`k = 2`
Therefore;
From;

`z = (kx)/(y)`

`z = (2x)/(y)`
Case 2:
z=?, x=10, y=12
From;

`z = (2x)/(y)`

`z = (2(10))/(12)`

`z = (20)/(12)`
Therefore;

`z = (5)/(3)`