Dan is cutting 4.75 foot length of twine from a 240 foot spoil of twine. He needs to cut 42 lengths and says that 40.5 feet of twine will remain. Show that this is reasonable

1 length is 4.75 feet

42 lengths = x feet Cross multiply

1 * x = 42 * 4.75 Multiply on the right

x = 199.5

amount left = amount started with - amount amount used

Amount left = ?

Amount started with = 240 feet.

Amount used = 199.5 Substitute

Amount left = 240 - 199.5 Subtract

Amount left = 40.5 Answer