17.75 pounds of flour
( excluding the .75)
17 x 19.68 = $334.56
.75 = 3/4
19.68 / 4 = $4.92
($4.92 for every quarter of a pound)
4.92 x 3 = $14.76 ( .75 = 3/4)
334.56 + 14.76 = $349.32
CHECK
17.75 x 4 = 71 ( Figure out how many fourths make 17.75)
71 x 4.92 = $349.32
She paid the shopkeeper $349.32