Answer:
y = 3.584
Step-by-step explanation:
Given
Variation = Inverse Proportional
When y = 7, x = 4
Required
Find y when x = 5
First, we need to represent the variation.
y varies inversely proportional to x³
This implies that
y ~ 1/x³
Convert variation to equation
y = k/x³
Make k the subject
k = x³y
When y = 7, x = 4
This gives:
k = 4³ * 7
k = 64 * 7
k = 448
To determine the value of y when x = 5;
We make use of y = k/x³
Substitute 5 for x and 448 for k
y = 448/5³
y = 448/125
y = 3.584
