void CalculateROI(GameEntity company)
{
// calculate ROI
var allChannels = Markets.GetAllMarketingChannels(Q);
maxROI = allChannels.Max(c => Marketing.GetChannelCostPerUser(company, c.marketingChannel.ChannelInfo.ID));
minROI = allChannels.Min(c => Marketing.GetChannelCostPerUser(company, c.marketingChannel.ChannelInfo.ID));
}