Several mountain climbers move up a mountain
starting from sea level. On the first day, they
climb up 1
2
of a mile. On the second day, they
move up the mountain 5
8
of a mile. On the third
day, they climb up 10
12 of a mile. On the fourth day,
bad weather forces them to climb down 4
6
of a
mile. How far above sea level are the climbers
after four days?