1/5 + 1/4 =1/x
4x + 5x = 20
9x = 20
x = 2.22 hours Answer
Answer:

Explanation:
You can put that equation into a program like desmos on your browser and take a screenshot or use windows snippet tool.
Equation of a Wave: y = Acos(((2*pi)/B)x)
or

A = Amplitude
B= Wavelength
For machines such as a rake the output force is less than the input force. If the input force of the rake is 10 newtons and the output force is 5 Newtons mechanical advantage is .5