A buyer of an appliance store bought a supply of electric fans at $1092 per electric fan. One-half of these electric fans were sold at $1349 each and the other half were sold at $1249. If the gross profit was $13500, how many electric fans were in the supply?

Solution -  rate =$1092 per fan

suppose there are x fans

then sold = 1349 (x/2) + 1249(x/2)

profit = sold - purchase = [ 1349 (x/2) + 1249(x/2)] - 1092 x = 13500

x(674.5+ 624.5 - 1092) = 13500

x = 13500/207 = 65.21