to find the ammount of twine left we subtract (twine used) from (total twine) or (total twine)-(twine used)=ammount left
so he must cut 42 legnths of rope each legnth is 4.75 and this is taken from a
total legnth of 240 so
240-42(4.75)=amount left
42 trimes 4.75=199.5
240-199.5=40.5 left