Question

s is inversely proportional to t . When s = 0.8 , t = 7 Work out s when t = 0.5

Answer 1

$\large\sf\underline{➪\:Given}$

$\sf\:s\:∝\frac{1}{t}$

$\sf\:s\:=\frac{k}{t}$-------(i)

• where k = constant of proportionality

$\large\sf\underline{➪\:To\:find}$

• s

$\large\sf\underline{➪\:Solution}$

$\sf\:When\:s=0.8\:and\:t=7\:lets\:find\:k$

$\sf⇒\:s\:=\frac{k}{t}$

$\sf⇒\:0.8\:=\frac{k}{7}$

$\sf⇒\:0.8\:=\frac{k}{7}$

$\sf⇒\:k\:=0.8 \times 7$

$\sf⇒\:k\:=\frac{8}{10} \times 7$

$\sf⇒\:k=\frac{56}{10}$

$\sf⇒\:k=5.6$

$\large\fbox\red{✰\:k\:=5.6}$

$\sf\:So\:now\:when\:t=0.5,\:k=5.6\:lets\:find\:s$

$\sf⇒\:s\:=\frac{k}{t}[from \:(i)]$

$\sf⇒\:s\:=\frac{5.6}{0.5}$

$\sf⇒\:s\:=\frac{56 \times 10}{5 \times 10}$

$\sf⇒\:s\:=\frac{560}{50}$

$\sf⇒\:s\:=\frac{56}{5}$

$\sf⇒\:s\:=11.2$

$\large\fbox\red{✰\:s\:=11.2}$

• Thnku ❣