Answer:
Dorsey = 4.8 hours
Campbell = 24 hours
Step-by-step explanation:
It takes "x" hours for Dorsey
So, it will take 5 times more for Campbell, so
It takes "5x" hours for Campbell
Rate is inverse of time, so rates are:
Dorsey: 1/x
Campbell: 1/5x
We know Rate * Time = Work
When together, it takes 4 hours to finish a work, so we can write:

Solving for x, we get the time of Dorsey:

Dorsey takes 4.8 hours alone
Campbell takes 4.8 * 5 = 24 hours alone
The answer to the question
Answer:
AE=22.4
Step-by-step explanation:
BE is 1/2 of BC
BC is 20 cm All sides of a square are equal
BE = 1/2 BC Property of a midpoint.
BE = 10
Now just use Pythagorus
AB^2 + BE^2 = AE^2
AE^2 = 20^2 + 10^2 Perform the sqrs
AE^2 = 400 + 100 Add the terms
AE^2 = 500 Take the square root of both sides
√AE^2 = √500
AE = 22.36
AE ≈ 22.4