Lionel walked 4 miles. Esther walked 975 yards and Niklaus walked 1287 feet. How many combined feet did the friends walk?
Lionel = 4 * 5280 = 21120 feet
Esther = 975 * 3 = 2925 feet
Together = 21120 + 2925 + 1287 = 25332 feet
Together the friends walked 25332 feet.