Question

Y is inversely proportional to V1+x. When x = 8, y = 2. Find y when x = 15.

Answer 1

Answer:

y = 1.5

Step-by-step explanation:

Given x is inversely proportional to $\sqrt{1+x}$ , then the equation relating them is

y = $\frac{k}{\sqrt{1+x} }$ ← k is the constant of proportion

To find k use the condition when x = 8, y = 2

2 = $\frac{k}{\sqrt{1+8} }$ = $\frac{k}{\sqrt{9} }$ = $\frac{k}{3}$ ( multiply both sides by 3 )

6 = k

y = $\frac{6}{\sqrt{1+x} }$ ← equation of proportion

When x = 15 , then

y = $\frac{6}{\sqrt{1+15} }$ = $\frac{6}{\sqrt{16} }$ = $\frac{6}{4}$ = $\frac{3}{2}$ = 1.5