CareerCup

If the fast worker is working at the rate of the slower one, then they are both working at the one house/6 days rate, so they will finish in 3 days.
If they can work completely independently, then they can complete 5/12 of a house per day (1/6 + 1/4), meaning a full house takes 12/5 = 2.4 days.

They both finish in 6 days, because the slower worker mentions that the "union" rep says 6 days to do the work, so they both agree and go have a beer.

ok, the correct answer is: 1/((1/4)+(1/6)) = 2.4 days. the faster won't be influenced by the slower because they will paint different areas.

The ratio is 1.5days:1day. The fast worker has to work at the rate of the slower work since they work together.

4/1.5=2.7 days

I was assuming the faster worker would not stay past 4 days. Otherwise, it would be 3 days.

20/9 days

This a paraLlel resistor problem like some have mentioned before:

1/[(1/6)+ (1/4)] = 2.4 DAYS

If you're confused with fractions, think of it this way.

Say there are 24 walls in the house. One can paint 4 walls per day (so 6 days), and the other can paint 6 walls per day (so 4 days). Together, they paint 10 walls per day => they take 2.4 days to paint the whole house.

Another way would be....

If total work is say x units.
person 1 can do x/6 units/day
person 2 can do x/4 units /day

Both can together do (x/6 + x/4) units/day
To complete x units of work both together can do it in x/(x/6+x/4) days which is 2.4 days.

Assuming they work independently (why shouldn't I) it takes 2.4 days.

Here is the calculation:
Worker 1 (x) needs 6 days and worker 2(y) needs 4 days.

So, x = 2y/3

Assume, they need together t days to finish the painting. So:

x*t + y*t = 4*y ( or 6*x)
2*y*t/3 + y*t = 4*y
5*y*t /3 = 4*y (we eliminite y)
t = 4*3 / 5 = 2.4 days

so, they need 2.4 days together.

A person finish the painting in 6 days. that means his one day work is 1/6 of total.
and B person finish the painting in 4 days. that means his one day work is 1/4 of total.
when both r to paint a home their one day work will be sum up to.  (1/4)+(1/6)=10/24
the whole painting is finished in=1/(10/24)=24/10=2.4
so they both will take 2.4 days to finish painting.

simple dude...
x=6
y=4
ans ,when both work together = (xy)/(x+y)
=(6x4)/(6+4)
=24/10
=2.4

Ans is 2.2 days.
6 days to make 1. so in 1 days he will make 1/6 part of painting
similarly other will make 1/4 part in one day.

When they both work together they will make 1/6+1/4 = 5/12 part of painting.
Now 1-5/12=7/12 part remains.

5/12 part is been made in 1 day
then 7/12 is been done in= (1/(5/12) )* 7/12 = 1.2 days.

So total days = 1.2+1 = 2.2 days.

2 days

0 days the house is already painted
ROFL :D