Given:
s is inversely proportional to t.
When s = 0.5, t = 7.
To find:
The value of s when t=0.8.
Solution:
s is inversely proportional to t.
[tex]s\propto \dfrac{1}{t}[/tex]
[tex]s=\dfrac{k}{t}[/tex] ...(i)
Where, k is the constant of proportionality.
Putting s=0.5 and t=7, we get
[tex]0.5=\dfrac{k}{7}[/tex]
[tex]0.5\times 7=k[/tex]
[tex]3.5=k[/tex]
Putting k=3.5 in (i), we get
[tex]s=\dfrac{3.5}{t}[/tex]
This is the equation of proportionality.
Putting t=0.8, we get
[tex]s=\dfrac{3.5}{0.8}[/tex]
[tex]s=4.375 [/tex]
Therefore, the value of s is 4.375 when t=0.8.