Question

A and B are positive numbers.A is inversely proportional to B.When A = 4, B = 36.Find the value of A when B = A

Answer 1

A = 12

Explanation:

Given A is inversely proportional to B then the equation relating them is

A =
`(k)/(B)`

To find k use the condition when A = 4, B = 36 , then

4 =
`(k)/(36)` ( multiply both sides by 36 )

144 = k

A =
`(144)/(B)` ← equation of variation

When B = A , then

A =
`(144)/(A)` ( multiply both sides by A )

A² = 144 ( take square root of both sides )

A = ±
`√(144)` = ± 12

Since A is a positive number then A = 12