Question

If b is directly promotional to a and b=3 when a=28,find the value of b when a=24

Answer 1

b =
`(18)/(7)`

Explanation:

given b is directly proportional to a , then the equation relating them is

b = ka ← k is the constant of proportionality

to find k , substitute b = 3, a = 28 into the equation

3 = 28k ( divide both sides by 28 )

`(3)/(28)` = k

b =
`(3)/(28)` a ← equation of proportionality

to find b when a = 24 , substitute a = 24 into the equation

b =
`(3)/(28)` × 24 ( cancel 28 and 24 by 4 )

b =
`(3)/(7)` × 6 =
`(3(6))/(7)` =
`(18)/(7)`