Question

R is inversely proportional to A.
R= 12 when A= 1.5
a) Work out the value of R when A = 5.
b) Work out the value of A when R = 9
Pleasee guys

Answer 1

Answer:

a) R = 3.6

b) A = 2

Step-by-step explanation:

Given that R is inversely to A (R ∝ 1/A) so the formula is R = k/A where k is a constant. So you have to find the value of k first by substituing R and A into the formula :

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

$let \: R = 12 \\ let \: A = 1.5$

$12 = \frac{k}{1.5}$

$12 \times 1.5 = k$

$k = 18$

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

We have already found the value of k. Next we only have to substitute the following values to find the value of other variable :

$let \: A = 5$

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

$let \: R = 9$

$9 = \frac{18}{A} \\ 9A = 18 \\ A = 18 \div 9 \\ A = 2$