Target Test Prep 20% Off Flash Sale is on! Code: FLASH20

Redeem
Target Test Prep
5-Day Free Trial
5-day free, full-access trial TTP

Available with Beat the GMAT members only code

MORE DETAILS
Target Test Prep
Magoosh
Magoosh
Study with Magoosh GMAT prep

Available with Beat the GMAT members only code

MORE DETAILS
Magoosh

combine rate question

This topic has expert replies
Post new topic Post Reply
Previous Topic Next Topic
Junior | Next Rank: 30 Posts
Posts: 13
Joined: Tue Jan 12, 2010 4:28 pm
Thanked: 1 times

combine rate question

by alwayslulu » Fri Apr 30, 2010 8:00 pm
Todd's construction company is able to build 40 houses per year. Mike's construction company builds 80 houses per year .

how long does it take the two companies together to build 64 houses?

Thanks for your response. :)
Top
Master | Next Rank: 500 Posts
Posts: 437
Joined: Sat Nov 22, 2008 5:06 am
Location: India
Thanked: 50 times
Followed by:1 members
GMAT Score:580

by beat_gmat_09 » Fri Apr 30, 2010 9:29 pm
alwayslulu wrote:Todd's construction company is able to build 40 houses per year. Mike's construction company builds 80 houses per year .

how long does it take the two companies together to build 64 houses?

Thanks for your response. :)
1/40 + 1/80 = x/64

x = 2.4
Top
GMAT Instructor
Posts: 1302
Joined: Mon Oct 19, 2009 2:13 pm
Location: Toronto
Thanked: 539 times
Followed by:164 members
GMAT Score:800

by Testluv » Fri Apr 30, 2010 10:18 pm
Together, the companies make 40 + 80 = 120 houses in one year. Thus:

120 houses/1 year = 64 houses/x years

x = 8/15 of a year or (8/15) * 365 = 194 and 2/3 days.
Kaplan Teacher in Toronto
Top
Master | Next Rank: 500 Posts
Posts: 437
Joined: Sat Nov 22, 2008 5:06 am
Location: India
Thanked: 50 times
Followed by:1 members
GMAT Score:580

by beat_gmat_09 » Fri Apr 30, 2010 11:04 pm
Testluv wrote:Together, the companies make 40 + 80 = 120 houses in one year. Thus:

120 houses/1 year = 64 houses/x years

x = 8/15 of a year or (8/15) * 365 = 194 and 2/3 days.
Hi Testluv,

I was under an impression to solve the problem using the standard rate formulaes, after looking at your solution it seemed obvious to me, how should one differentiate between such problems weather to solve using the standard formulaes or to apply logic as you applier above.

Thanks
Top
Post new topic Post Reply
• Page 1 of 1