Question

Suppose y varies directly with x if y=27 when x=3 what is y when x=5

Answer 1

The value of y when x = 5 is 45

Solution:

Given that y varies directly with x. This can be written mathematically as:

y ∝ x

`y = k * x` ---- eqn 1

Where "k" is the constant of propotionality

Given y = 27 when x = 3. Substitute these values in eqn 1

`27 = k * 3\\\\k = (27)/(3) = 9`

k = 9

Substitute k = 9 in eqn 1

y = 9x ----- eqn 2

To find: y = ? and x = 5

Substitute x = 5 in eqn 2

`y = 9 * 5 = 45`

Thus the value of y when x = 5 is 45