Question

Question 66

If x varies inversely as y and y = 60 when x = 1.5. Find x, when y = 4.5

Answer 1

If x varies inversely as y.
$\therefore xy$=k(constant)...(i)

If x = 1.5 and y = 60
$\therefore xy=1.5\times 60=90\Rightarrow k=90$

When y = 4.5, then from Eq.(i),
$4.5\times x=k$
$\Rightarrow 4.5\times x=90$ [Putting the value of k]
$\Rightarrow x=\frac{90}{4.5}=20$