Divide total length ( 36 inches) by the length of one paper clip ( 3/4 inch) to find the total number of paper clips:
36 / 3/4 = (36*4) /3 = 144 / 3 = 48
They used 48 total paper clips.
Each paper clip cost $0.02.
Multiply the total number of clips by the cost for one:
48 x 0.02 = 0.96
Total cost is $0.96