First we need to know how many meters that there are in a yard which is 1meter=1.09361 yards so now we need to find out how many meters that there are in 15 yards which is 13.716 now we take that times 2 because she can make 2 out of 1 meter which is 27.432 so the seamstress here can make roughly 27 aprons from 15 yards of fabric.
Enjoy!=)