Two painters are working together and can paint a house in 3 hours. one painter alone can paint the same house in 8 hours. how many hours would it take the second painter to paint the house by himself

For this case, the first thing we must do is define a variable.
 We have then:
 x: number of hours it takes the second painter to paint the house working alone.
 We have then that the equation that models the problem is:
 
 From here, we clear the value of x.
 We have then:
 
 
 
 
 
 
 
 It would take the second painter to paint the house by himself about 4.8 hours.