Question

Suppose that y varies inversely with x. Use the information to find k, and then choose the equation of variation. x = 1.2 when y = 3.

Answer 1

Y = k/x where k is the constant of variation
y = 3 , x = 1.2 gives
3 = k/1.2
therefore 
k = 3*1.2 = 3.6
and the  required equation is 

y = 3.6 / x