Answer:
y = 0.64/x^3
Step-by-step explanation:
If y is inversely proportional to a^3, we can write the equation:
y * a^3 = k
Using a = 2 and y = 10, we have:
10 * 2^3 = k
k = 80
If a is directly proportional to x, we can write the equation:
a = c * x
Using x = 4 and a = 20, we have:
20 = c * 4
c = 5
Now, using the value of a = 5*x in the equation y * a^3 = 80, we have:
y * (5x)^3 = 80
y * 125x3 = 80
y = 80/(125x3) = 0.64/x^3