Moving Walkways

The speed of a moving walkway is
typically about 2.5 feet per second. Walking on such a
moving walkway, it takes Karen a total of 40 seconds to
travel 50 feet with the movement of the walkway and then
back again against the movement of the walkway.What is
Karen’s normal walking speed?

Work problems

Pedro can paint a fence 50% faster than Juan and 20% faster than Pilar and together they can paint a given fence in 4 hours. How long will it take Pedro to paint the same fence if he had to work alone?

Solution:
Let Rate of pedro = 1/tpedro = x
Rate of juan = .50x
Rate of pilar = .80x
(x+.50x+.80x)4=1
2.3x=1/4
x=5/46
5/46 = 1/tpedro
tpedro=46/5 =9.2hours