Question

If y varies inversely with x, and y=8 when x=10 find x when y=4

Answer 1

Answer:

x = 4

Step-by-step explanation:

Given y varies inversely as x then the equation relating them is

y = $\frac{k}{x}$ ← k is the constant of variation

To find k use the condition y = 8 when x = 10

k = yx = 8 × 10 = 80

y = $\frac{80}{x}$ ← equation of variation

When y = 4, then

4 = $\frac{80}{x}$ ( multiply both sides by x )

4x = 80 ( divide both sides by 4 )

x = 20