Question

I’ve been having trouble with this question as I haven’t learnt it yet.

Answer 1

R = $\frac{18}{5}$ = 3.6 and A = 2

given that R is inversely proportional to A, then

R = $\frac{k}{A}$ ← k is the constant of variation

To find k use the condition R = 12 when A = 1.5

k = RA = 12 × 1.5 = 18

the equation is therefore

R = $\frac{18}{A}$

when A = 5, then

R = $\frac{18}{5}$ = 3.6

when R = 9, then

9 = $\frac{18}{A}$ ( multiply both sides by A )

9A = 18 ( divide both sides by 9 )

A = 2