I do not understand the question

Question

Luis can cut and split cord of wood twice as fast as Blake can. when they work together, it takes them 4 hours. How long would it take each of them to do the job alone

Answer 1

If Luis takes x hours alone, then Blake takes 2x hours

 

So Luis does 1/x parts per hour

and Blake does 1/2x parts per hour

Together they do  1/x + 1/2x = 3/(2x) parts per hour

 

4(3/2x) = 1

3/(2x) = 1/4

3 = (2x)/4

2x = 12

x = 6

 

Luis would take 6 hours alone

Blake would take 2x=12 hours alone