Live GMAT classes with Target Test Prep start Nov 21 and Nov 22. First class free.

See classes
Target Test Prep · GMAT

Choose how you want to prepare

Learn live with an expert or move at your own pace. Every option includes the complete TTP study system.

Newsweek Readers’ Choice Awards 2026 winner: Target Test Prep, #1 Test Prep

Target Test Prep was voted #1 Best Test Prep in the 2026 Newsweek Readers’ Choice™ Awards.

★★★★★5.0563 reviews
GMATLiveTeachStarts Nov 22
Josh Braslow, Target Test Prep GMAT expert
LIVE ONLINE CLASSES

Get Ready for GMAT Test Day Faster with Live Online Classes

with Josh Braslow, 20+ years in test prep

Nov 22 · Josh Braslow
Sun · 9:30 AM to 12:30 PM ET
Included
40 hours of live online classes + 6 months of TTP OnDemand
  • Attend the first class for free
  • Every class is recorded, so you never fall behind
View classes & enroll
Limited seats availableTarget Test Prep
EALiveTeachOnDemandStart anytime
EXECUTIVE ASSESSMENT

Target Test Prep EA OnDemand

Self-paced EA prep. Study on your schedule.

EXECUTIVE ASSESSMENT

with

165+ EA score guarantee
$05-day trial no automatic billing
Schedule
Included
40 hours of live online classes plus six months of access to the complete TTP EA OnDemand course.
  • 165+ EA Score Guarantee
  • 4,100+ Quant, Verbal, and Integrated Reasoning practice questions
  • 400+ hours of in-depth video lessons
  • 3,000+ step-by-step video solutions
View EA class & enroll Start free 5-day trial
Limited cohort · enrollment openTrial includes full course accessTarget Test Prep
GMATOnDemandStart anytime
SELF-PACED MASTERCLASS

Target Test Prep GMAT OnDemand

Complete access from day one. Study on your schedule.

715+ score guarantee
$0to start then $127/mo
  • Personalized study plan and analytics
  • Thousands of lessons and practice questions
Start free 5-day trial
Read 563 reviewsTarget Test Prep

Proportions and Unknown multiplier problem

Expert replies
Post new topic Post Reply
Subscribe topic
Previous Topic Next Topic
Legendary Member
Posts: 641
Joined: Tue Feb 14, 2012 3:52 pmFollowed by: 8 members
Thanked: 11 times
by gmattesttaker2 » Thu Jul 05, 2012 11:03 pm
Hello,

This is from MGMAT Guide 1 (5th edition):

Alexandra needs to mix cleaning solution in the following ratio: 1 part bleach for every 4 parts water. When mixing the solution, Alexandra makes a mistake and mixes in half as much bleach as she ought to have. The total solution consists of 27 ml. How much bleach did Alexandra put into the solution?

Answer given is 3 ml


Any suggestions on how to solve this problem? Thanks a lot.

Best Regards,
Sri
Top
Join the discussion
Source: — Problem Solving |
User avatar
Legendary Member
Posts: 520
Joined: Sat Apr 28, 2012 9:12 pmFollowed by: 49 members
Thanked: 339 times
GMAT Score:770

by eagleeye » Fri Jul 06, 2012 3:16 am
For the proper ratio, we need:

1 part bleach: 4 parts water = 1:4
If only half of bleach is put in, the ratio becomes
1/2 : 4 = 1:8

Let amount of bleach that Alexandra put in the solution is x. Then amount of water = 8x.
Now total amount = x+8x = 9x.
We are given that 9x=27 => x=3.
Top
Join the discussion
User avatar
GMAT Instructor
Posts: 1248
Joined: Thu Mar 29, 2012 2:57 pmFollowed by: 192 members
Location: Everywhere
Thanked: 503 times
GMAT Score:780

by Bill@VeritasPrep » Fri Jul 06, 2012 5:40 pm
eagleeye wrote:For the proper ratio, we need:

1 part bleach: 4 parts water = 1:4
If only half of bleach is put in, the ratio becomes
1/2 : 4 = 1:8

Let amount of bleach that Alexandra put in the solution is x. Then amount of water = 8x.
Now total amount = x+8x = 9x.
We are given that 9x=27 => x=3.
This is the best approach. Take the original ratio, apply the change given (half as much bleach), and then incorporate the actual amount (27 mL).
Join Veritas Prep’s 2010 Instructor of the Year, Matt Douglas for GMATT Mondays

Visit the Veritas Prep Blog

Try the FREE Veritas Prep Practice Test
Top
Join the discussion
Newbie | Next Rank: 10 Posts
Posts: 4
Joined: Sat Jun 16, 2012 10:28 pm

by windchaser » Mon Jul 09, 2012 12:15 am
This is my approach:
original ratio is 1:4
half as much as she ought to have, means it is now 0.5 : 4
27/4.5= 6
6*0.5 = 3mL
Top
Join the discussion