Aworm is climbing out of a 20 in. hole. the worm climbs 4 inches during each day and at night falls back 10% of the height the worm is above the hole. at the beginning of the fourth day, how far is the worm from the top of the hole?

First day
ok so 4 inches up means 4 iches above the bottom, 10% of 4 is 0.4, and 4-0.4=3.6

second day
3.6+4=7.6, now 10% of that is 0.76, 7.6-0.76=6.84

third day
6.84+4=10.84, 10% of 10.84 is 1.084, 10.84-1.084=9.756

fourth day, at begining is at the end of third

worm is 9.756 in above the bottom of hole
20-heightup=height from top
20-9.756=10.224

answer is 10.224 inches from top