BREAKING: Target Test Prep releases Brand New 2026 On Demand GMAT prep course

Redeem

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.

★★★★★5.0559 reviews
Vote for Target Test Prep, Newsweek Readers’ Choice Awards 2026
NEWSWEEK READERS’ CHOICE 2026

BIG NEWS! Target Test Prep has been nominated, and they’d love your vote!

TTP has worked incredibly hard to build the best test prep experience possible, and winning Newsweek’s 2026 Readers’ Choice Award for Best Test Prep would mean a lot to them. If TTP has helped you, they’d be incredibly grateful for your vote. You can vote once each day through September 9.

Vote for TTP
GMATLiveTeach 7 seats left
Chris Peckover
NEXT LIVE COHORT

Oct 13 to Jan 7, 2027

with Chris Peckover

Schedule
Tue, Thu · 8:00 to 10:00 PM ET
Included
40 live hours + 6 months of GMAT OnDemand
  • Live instruction and real-time questions
  • Class recordings and assigned practice
View class & enroll
Limited cohort · enrollment openTarget Test Prep
EALiveTeach 5 seats left
Logan Thompson
EXECUTIVE ASSESSMENT

Sep 6 to Dec 6, 2026

with Logan Thompson

Schedule
Sun · 9:30 AM to 12:30 PM ET
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
Limited cohort · enrollment openTarget Test Prep
GMATOnDemand Start 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 559 reviewsTarget Test Prep

Compare the format, schedule, and included access before enrolling. Prices and seat counts shown reflect the supplied offer details.

In a certain class, the ratio of girls to boys is 5:4. How many girls are there? (1) If four new boys joined the class,

Expert replies
Post new topic Post Reply
Previous Topic Next Topic
Moderator
Posts: 7187
Joined: Thu Sep 07, 2017 4:43 pmFollowed by: 23 members
by BTGmoderatorDC » Sat Jan 18, 2020 2:12 pm
In a certain class, the ratio of girls to boys is 5:4. How many girls are there?

(1) If four new boys joined the class, the number of boys would increase by 20%.

(2) If the number of girls increases by 50%, then after such an increase, the probability that a randomly chosen student would be a boy would be 8/23



OA A

Source: Magoosh
Top
Join the discussion
Log in to postLogin with Googleuse password
QUOTE IN REPLY
Source: — Data Sufficiency |

GMAT/MBA Expert

User avatar
GMAT Instructor
Posts: 3008
Joined: Mon Aug 22, 2016 6:19 amFollowed by: 34 members
Location: Grand Central / New York
Thanked: 470 times

Re: In a certain class, the ratio of girls to boys is 5:4. How many girls are there? (1) If four new boys joined the cl

by Jay@ManhattanReview » Sun Jan 19, 2020 11:02 pm
BTGmoderatorDC wrote: ↑
Sat Jan 18, 2020 2:12 pm
 In a certain class, the ratio of girls to boys is 5:4. How many girls are there?

(1) If four new boys joined the class, the number of boys would increase by 20%.

(2) If the number of girls increases by 50%, then after such an increase, the probability that a randomly chosen student would be a boy would be 8/23

OA A

Source: Magoosh
\

Given that the ratio of girls to boys is 5 : 4, say there are 5x girls and 4x boys. We have to get the value of 5x.

Let's take each statement one by one.

(1) If four new boys joined the class, the number of boys would increase by 20%.

=> 5x / (4x + 4) = 5 / (4*120%) = 5/4.8 = 25/24

(5/4)*[x/(x + 1)] = 25/24 => x = 5

Thus, 5x = 5*5 = 25. Sufficient

(2) If the number of girls increases by 50%, then after such an increase, the probability that a randomly chosen student would be a boy would be 8/23.

Currently, there are 5x girls and 4x boys; after the increase, the number of girls = 5x*150% = 7.5x

So, now there are 7.5x girls and 4x boys; thus, the total no. of students = 7.5x + 4x = 11.5x

Thus, the probability that a randomly chosen student would be a boy = 4x/11.5x = 40/115 = 8/23. We already know this. Statement 2 does not provide additional information. Insufficient.

The correct answer: A

Hope this helps!

-Jay
_________________
Manhattan Review

Locations: Manhattan Review Begumpet | GMAT Prep Visakhapatnam | GRE Prep Warangal | Dilsukhnagar GRE Coaching | and many more...

Schedule your free consultation with an experienced GMAT Prep Advisor! Click here.
Top
Join the discussion
Log in to postLogin with Googleuse password
QUOTE IN REPLY
Legendary Member
Posts: 2564
Joined: Sun Oct 29, 2017 2:04 pmFollowed by: 6 members

Re: In a certain class, the ratio of girls to boys is 5:4. How many girls are there? (1) If four new boys joined the cl

by swerve » Mon Jan 20, 2020 12:03 pm
BTGmoderatorDC wrote: ↑
Sat Jan 18, 2020 2:12 pm
 In a certain class, the ratio of girls to boys is 5:4. How many girls are there?

(1) If four new boys joined the class, the number of boys would increase by 20%.

(2) If the number of girls increases by 50%, then after such an increase, the probability that a randomly chosen student would be a boy would be 8/23



OA A

Source: Magoosh
Given the ratio of B/G = 5/4.

Statement 1: B+ 4= 1.2 B ie B = 20 , can find out girls. Sufficient \(\Large{\color{green}\checkmark}\)

Statement 2: Probability boy would be selected after girls increase by 50 % = B / B + 1.5 G = 8/23.
ie B/G = 4/5. Not sufficient \(\Large{\color{red}\chi}\)

Hence, the correct answer is __A__
Top
Join the discussion
Log in to postLogin with Googleuse password
QUOTE IN REPLY
Post new topic Post Reply
• Page 1 of 1