Question

H varies directly to the cube of c.
When H = 40, C = 2.
Find the value of H when c=5

Answer 1

H = 625

Explanation:

Given H varies directly as c³ then the equation relating them is

H = kc³ ← k is the constant of variation

To find k use the condition when H = 40, c = 2, then

40 = k × 2³ = 8k ( divide both sides by 8 )

5 = k

H = 5c³ ← equation of variation

When c = 5, then

H = 5 × 5³ = 5 × 125 = 625