Verified Answer :

1 foot = 12 inches

Graham's = 24 inches
Katie's = 20 inches

the answer is 4 inches

1 foot=12 inches so, if graham has 2 feet and Katie has 1 feet 8 inches.that means that graham has (2) 12+12=24.Katie has (1&8inches)12+8=20.so you subtract 24-20 which =4. So,Graham has 4 more inches than Katie.