Answer:
15% above the trend.
Explanation:
A time series represented by Y comprises of dataset observed over a particular period of time. Time series is handy in determining the future of a particular business.
In a multiplicative model, if the seasonal factor is 1.15 for a particular season, then we expect that the time series in that season would be
Y = T × C × S × 1
where;
Seasonal S = 1.15
As such Y would increase by 15% above the trend if all other things are being equal.