



 
Hi Meghan, A friend of mine knits wool hats for the cold winters here in Saskatchewan and sells them at a local craft store. In the winter of 2008/09 she sold $N$ hats. In the winter of 2009/10 she had a $20\%$ increase in sales so she sold $N \times 1.2$ hats in the winter of 2009/10. Sales increased again the following year, this time by $30\%$ and hence in 2010/11 she sold $(N \times 1.2) \times 1.3 = N \times 1.56$ hats. The winter of 2011/12 was especially warm and she didn't sell as many hats, in fact the sales decreased by $40\%$ and hence she only sold $60\%$ of what she sold in the previous year. Thus her sales in 2011/12 were $((N \times 1.2) \times 1.3) \times 0.60 = N \times 0.936$ hats. This winter in cold so I expect her sales will increase again but it is too early to tell. Penny  


Math Central is supported by the University of Regina and The Pacific Institute for the Mathematical Sciences. 