Question

Y is directly proportional to x^ . if y=12 when x=2 find, y when x=5

Answer 1

The value of y = 30 when x = 5

Explanation:

We know that when 'y' varies directly proportional to 'x', we get the equation

y ∝ x

y = kx

k = y/x

where k is called the 'constant of direct variation'.

We are given

y = 12 when x = 2

so substituting y = 12 and x = 2 in the equation

k = y/x

k = 12/2

k = 6

Thus, the value of k = 6

We have to determine the value of y when x = 5

so substitute x = 5 and k = 6 in the equation

y = kx

y = 6(5)

y = 30

Therefore, the value of y = 30 when x = 5