Given:
Y varies directly with X,
Y = 10 when x = 8
To find:
Value of x when y = 30.
Step-by-step solution:
As per the question:
Y is directly proportional to x:
y ∝ x
y = kx
Also y = 10 when x = 8:
10 = k(8)
k = 10/8 = 5/4
The final equation in terms of x and y:
y = 5x / 4
Value of x when y = 30:
y = 5x / 4
30 = 5x / 4
120 = 5x
x = 24
Thus we can say that the value of x, in this case, is equal to 24