Simplify the equation

Assume that y varies inversely with x. if y=1.6 when x=0.5 find x when y=3.2

Astore sells 4 apples for $3 and 3 oranges for $4 if pete buys 12 apples and 12 oranges how much will it cost

In a small section of a stadium there are 40 spectators watching a game between the cook islands and fiji. they all support at least one of the two teams. 25 spectators support the cook islands and 16 of these support both teams. how many support only fiji?