Confirming my work. Thank you!

Mr. N can paint his house by himself in four days. His son will need an additional two days to complete the job if he works by himself. If they work together, find how long it takes to paint the house.

Chart:

---- days for total job part in 1 day
Mr. D. 4 1/4
Mr. D.'s son Mr. D total plus 2, or 4+2 = 6 1/6
Together x 1/x

FORMULA: 1/4 + 1/6 = 1/x

METHOD

LCM is 12x, so

12x (1/4) + 12x(1/6) = 12x(1/x)

3x + 2x = 12

combine 5x = 12

divide by 5 5x/5 = 12/5

x = 12/5 or 2 2/5 days

Question

Confirming my work.  Thank you!

 

Mr. N can paint his house by himself in four days.  His son will need an additional two days to complete the job if he works by himself.  If they work together, find how long it takes to paint the house.

 

Chart:

----	days for total job	part in 1 day
Mr. D.	4	1/4
Mr. D.'s son	Mr. D total plus 2, or 4+2 = 6	1/6
Together	x	1/x
 	 	 

FORMULA:  1/4 + 1/6 = 1/x

METHOD

LCM is 12x, so

 

12x (1/4) + 12x(1/6) = 12x(1/x)

3x + 2x = 12

combine  5x = 12

divide by 5    5x/5 = 12/5

                 x = 12/5 or 2 2/5 days

ash2326 · Answer

Absolutely correct ;D