ANSWER ASAP PLEASE !!!AND CORRECT!!
OTHER ANSWER CHOICE IS 19 feet, 6 inches.

well you know that the yellow rope is 18' shorter then the white rope X 2,
so you would take 101/2 feet and add 18 inches, then you would need to divide that by two to get how long the white one is.
10 1/2 feet + 18 inches = 12 feet
12 feet divided by 2 is 6 feet