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It would take them 4 hours to paint the house together.

Q: It takes Sal 5 hours to paint a house It takes Sal 3 hours to paint the same house How long will it take to paint the house if both of them work together?

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You don't need a formula. You need to understand where the answer comes from. If you understand where the answer comes from, you can write your own formula. If you don't, then a formula can be dangerous in your hands. -- Sally can paint 1/4 of the house in an hour. -- John can paint 1/6 of the same house in an hour. -- If they work together, then can paint (1/4 + 1/6) = 5/12 of the house in an hour. -- If they paint 5/12 of the house in an hour, then it takes them 12/5 hours to finish the job, or 2.4 hours, or 2hours 24minutes. Well, OK. Here's the formula: S = number of hours it takes Sally J = number of hours it takes John Number of hours it takes them working together = 1 / (1/S + 1/J)

Sally does 1 job in 4 hours ===> 1/4th of the job per hour.John does 1 job in 6 hours ===> 1/6th of the job per hour.Working together, they do (1/4 + 1/6) = (3/12 + 2/12) = 5/12 job per hour.The job takes 12/5 = 2.4 hours = 2hours24minutes to complete.

1.5 hours + 2 hours = 3.5 hours So 3.5 hours in total!

Less than two hours.

8 hours...think of it as a ratio: 5/10=4/?

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You don't need a formula. You need to understand where the answer comes from. If you understand where the answer comes from, you can write your own formula. If you don't, then a formula can be dangerous in your hands. -- Sally can paint 1/4 of the house in an hour. -- John can paint 1/6 of the same house in an hour. -- If they work together, then can paint (1/4 + 1/6) = 5/12 of the house in an hour. -- If they paint 5/12 of the house in an hour, then it takes them 12/5 hours to finish the job, or 2.4 hours, or 2hours 24minutes. Well, OK. Here's the formula: S = number of hours it takes Sally J = number of hours it takes John Number of hours it takes them working together = 1 / (1/S + 1/J)

One day.

Sally does 1 job in 4 hours ===> 1/4th of the job per hour.John does 1 job in 6 hours ===> 1/6th of the job per hour.Working together, they do (1/4 + 1/6) = (3/12 + 2/12) = 5/12 job per hour.The job takes 12/5 = 2.4 hours = 2hours24minutes to complete.

1.5 hours + 2 hours = 3.5 hours So 3.5 hours in total!

Less than two hours.

8 hours...think of it as a ratio: 5/10=4/?

We know that Sally can paint the house by herself in four hours. Put another way, she can paint 1/4 of the house in an hour. Using similar logic, we know John paints at a rate of just 1/6 of a house per hour. If we convert those fractions to fractions with a common denominator, we have 3/12 of a house for Sally and 2/12 of a house for John, so together they can paint at a rate of 5/12 of a house per hour. But that is not yet the answer to the question. If you take the reciprocal of 5/12 houses per hour, you get 12/5 hours per house. That equals 2.4 hours per house. Converting to hours and minutes, you get 2 hours, 24 minutes -- because 0.4 hours equals 24 minutes. (0.4 hours x 60 minutes/hour = 24 minutes.) Algebra OR Above answer of this question is right.but we can also define it some other way, in percentage. May be this solution make esay for some friends to understand.Silly tooks 4 hors to paint 100 % (full house).Jhon tooks 6 hours to paint 100 % (Full house).In an hoursilly can paint 25 % of house & Jhon can paint 16.66 % of house, so they both can paint 41.66 percent of house in an hour.so, if we divide (total required work) / (work they can do in an Hour)= 100 / 41.66we I'll get the total time to paint complete house.ANSWERS IS : 2.4 Hours or 2 hours 24 minutes.

Multiply 3 and 5 to get a Least Common Multiple. 15. So you find how many rooms can Alvin paint in 15 hours (5 rooms). Same with Bernie (3 rooms). That means they can paint 8 rooms in 15 hours. Since you want to find "how long it would take," you flip the rate over. In 15 hours they can paint 8 rooms. Reduce if you want, 15/8= 1.875 hour to paint one room.

It will take about 11.1 hours for the two of them to complete the roofing of the house.

One hour is saved. The three guys need two more hours to finish. If three more guys help them, it will cut the time in half. 3 guys * 5 hours = 1 house painted guy * hour = 1 hour of labor So it would take 15 hours of labor to paint a house. We need to assume houses take the same time to paint and each guy works at the same rate. 3 guys * 3 hours = 9 hours of labor 9 hours of labor + (3+3) guys * x hours = 15 hours of labor 9 + 6x = 15 x=1 Total time = 3 hours of 3man + 1 hour of 6 man = 4 hours time saved = 5-4 = 1 hour

Assuming that there is no synergy, nor time wasted when the two of them start chatting, M paints 0.2 rooms per hour F paints 0.166.. rooms per hour so M + F paint 0.366... rooms per hour So it takes them 1/0.366... = 2.7272... hours

it takes about 3 and a half hours to dry in a living room