Mr. Simmons figures he can paint his house in 5 days. If his son helps, together they can paint it in 2 days. How long will it take his son to paint the house if he works alone?

Answer 1

Hi Zoie,

Formula for this type of work problem is (1/a) + (1/b) = (1/c)

a=first worker's time

b=second worker's time

c=time together

Here:

a=5, Mr. Simmons' time

b=b, his son's time, which we are looking for

c=2, time it takes them together

So:

(1/5) + (1/b) = (1/2)

Get x term alone:

(1/b)= (1/2) - (1/5)

Find a common denominator:

(1/b)= (5/10) - (2/10)

(1/b) = 3/10

Take the reciprocal of both sides (reverse numerators and denominators):

b=10/3

b=3.33 days

I hope this helps.