Given:

4 cookies + 6doughnuts + 3 doughnut holes boxes = $8.15......(i)

2 cookies + 3 doughnuts + 4 doughnut holes boxes= $7.20.....(ii)

Multiply (ii) by 2 we have

4 cookies + 6 doughnuts + 8 doughnut hole boxes = $14.4..(iii)

Subtracting (i) from(iii) we have

5 doughnut hole boxes = $6.25
=> 1 doughnut hole box= 6.25/5 =$1.25 (OPTION E)