Question

y is directly proportional to x when y=30, x=6 a) work out an equation connecting y and x b) work out the value when x=12

Answer 1

a) y = 5x

b) y = 60

Explanation:

a) Standard equation of direct proportion:

y = kx

We need to find k. We can use the given values of x and y to find k.

x = 6; y = 30

30 = k * 6

k = 30/6 = 5

Now we use k = 5 in the standard equation to get this problem's direct proportion equation.

y = 5x

b)

x = 12

y = 5x

y = 5 (12)

y = 60