Thank you for using the timer - this advanced tool can estimate your performance and suggest more practice questions. We have subscribed you to Daily Prep Questions via email.

Customized for You

we will pick new questions that match your level based on your Timer History

Track Your Progress

every week, we’ll send you an estimated GMAT score based on your performance

Practice Pays

we will pick new questions that match your level based on your Timer History

Not interested in getting valuable practice questions and articles delivered to your email? No problem, unsubscribe here.

It appears that you are browsing the GMAT Club forum unregistered!

Signing up is free, quick, and confidential.
Join other 350,000 members and get the full benefits of GMAT Club

Registration gives you:

Tests

Take 11 tests and quizzes from GMAT Club and leading GMAT prep companies such as Manhattan GMAT,
Knewton, and others. All are free for GMAT Club members.

Applicant Stats

View detailed applicant stats such as GPA, GMAT score, work experience, location, application
status, and more

Books/Downloads

Download thousands of study notes,
question collections, GMAT Club’s
Grammar and Math books.
All are free!

Thank you for using the timer!
We noticed you are actually not timing your practice. Click the START button first next time you use the timer.
There are many benefits to timing your practice, including:

0% (00:00) correct
0% (00:00) wrong based on 0 sessions

could some one tell me the formula for ansewring this question?

If Sally can paint a house in 4 hours, and John can paint the same house in 6 hour, how long will it take for both of them to paint the house together?

A. 2 hours and 24 minutes B. 3 hours and 12 minutes C. 3 hours and 44 minutes D. 4 hours and 10 minutes E. 4 hours and 33 minutes

If Sally can paint a house in 4 hours, and John can paint the same house in 6 hour, how long will it take for both of them to paint the house together?

A. 2 hours and 24 minutes B. 3 hours and 12 minutes C. 3 hours and 44 minutes D. 4 hours and 10 minutes E. 4 hours and 33 minutes

Sally -a house in 4 hrs 1 hr -1/4

John -a house in 6 hrs 1 hr -1/6

Together sally and John in one hour complete 1/4+1/6 =6+4/24=10/24 =5/12

1 hr - 5/12 part of the house ? hr - whole house

Whole house = 12/5 =2 hrs 24 min _________________

Keep trying no matter how hard it seems, it will get easier.

Someone please correct me if I'm wrong. I'm a little rusty with rate/work problems.

Know this formula: R*T = W (Rate)*(Time) = Work

Sally: Rate * 4 hours = 1 house Rate = 1/4

John: Rate * 6 hours = 1 house Rate = 1/6

Working together, you combine their rates. So working together, their rate is: 1/4 + 1/6 = 10/24

So go back to the original equation R*T = W and make a new one with this new information. What do we know? Their rate is 10/24 houses/hour. They are going to paint 1 house (this is W). We need to find the time it takes (T). So we have:

(10/24)*T = 1 T = 24/10 = 12/5 hours

This is 2 and 2/5 hours. 2/5 of one hour is 24 min. So it will take 2 hours and 24 min. Answer A.

Also note that you can immediately eliminate answer choices D and E because Sally takes only 4 hours to paint a house. If John helps, no matter how slow/fast he paints, it will take less than 4 hours.

wud just like to contribute a simpler method which i found very useful in doing faster calculations.

this method works for all "rate of doing work" problems, including distance and speed.

When rate of work is given, we usually have to calculate using reciprocals. instead take the lcm of all the rates of work of different people. ie, here 4 hrs and 6 hrs,,,,,, lcm = 12

consider this lcm to be the total units of work to be done, ie, 12 units to be painted

Then, sally can paint the 12 units in 4 hours, or per hour she paints 3 units. John paints 12 in 6 hours, so per hour he paints 12/6 = 2 units

Now both working together will paint 3+2 = 5 units per hour

To paint 5 units they take 1 hour, so to paint 12 units they will take 12/5 hours.

This method is excellent for doing simple calculations mentally. No need to use pen and paper. Try applying it to all time and work or speed and distance problems while practicing.

I worked it out the normal way as well and got confused by \(12/5 = 2.4\) so 2 hours and 40% of 60 minutes.. Is there is way not to confuse when converting the decimals to hours and minutes ?

I worked it out the normal way as well and got confused by \(12/5 = 2.4\) so 2 hours and 40% of 60 minutes.. Is there is way not to confuse when converting the decimals to hours and minutes ?

Donno if this helps, but I try to avoid using decimals when working with hr & minutes.

What I try to do is write the number as 2 2/5, however you still have to remember that 2/5 is of 60, not 100.

Hey, Last week I started a few new things in my life. That includes shifting from daily targets to weekly targets, 45 minutes of exercise including 15 minutes of yoga, making...

This week went in reviewing all the topics that I have covered in my previous study session. I reviewed all the notes that I have made and started reviewing the Quant...

I started running as a cross country team member since highshcool and what’s really awesome about running is that...you never get bored of it! I participated in...