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
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

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

ratio cross cancel method

Expert replies
by shahab03 » Sun May 20, 2012 8:33 am
can someone please explain in detail how to do this problem using cross cancel method... i was able to do it by bringing all the values to same level but that takes too long would like to do it faster. thanks


At a certain school, the ratio of the number of second
graders to the number of fourth graders is 8 to 5, and
the ratio of the number of first graders to the number of
second graders is 3 to 4. If the ratio of the number of
third graders to the number of fourth graders is 3 to 2 ,
what is the ratio of the number of first graders to the
number of third graders?

(A) 16 to 15
(B) 9 to 5
(C) 5 to 16
(D) 5 to 4
(E) 4 to 5
Join the discussion
Source: — Problem Solving |

by Anurag@Gurome » Sun May 20, 2012 8:44 am
shahab03 wrote:can someone please explain in detail how to do this problem using cross cancel method... i was able to do it by bringing all the values to same level but that takes too long would like to do it faster. thanks


At a certain school, the ratio of the number of second
graders to the number of fourth graders is 8 to 5, and
the ratio of the number of first graders to the number of
second graders is 3 to 4. If the ratio of the number of
third graders to the number of fourth graders is 3 to 2 ,
what is the ratio of the number of first graders to the
number of third graders?

(A) 16 to 15
(B) 9 to 5
(C) 5 to 16
(D) 5 to 4
(E) 4 to 5
Let the number of 1st, 2nd, 3rd and 4th graders be A, B, C and D respectively.
Then we have to find A : C.

B/D = 8/5
A/B = 3/4
C/D = 3/2

Now B/D = 8/5 = (8 * 2)/(5 * 2) = 16/10
C/D = 3/2 = (3 * 5)/(2 * 5) = 15/10
A/B = 3/4 = (3 * 4)/(4 * 4) = 12/16

A/C = (A/B) * (B/D) * (D/C) = (12/16) * (16/10) * (10/15) = 12/15 = [spoiler]4/5[/spoiler]

The correct answer is E.
Anurag Mairal, Ph.D., MBA
GMAT Expert, Admissions and Career Guidance
Gurome, Inc.
1-800-566-4043 (USA)

Join Our Facebook Groups
GMAT with Gurome
https://www.facebook.com/groups/272466352793633/
Admissions with Gurome
https://www.facebook.com/groups/461459690536574/
Career Advising with Gurome
https://www.facebook.com/groups/360435787349781/
Join the discussion

by eagleeye » Sun May 20, 2012 8:49 am
Hi Shahab03:

I don't know what the cross cancel method is but this is how I did it and it didn't take more than 30 seconds. Let First, Second,Third, Fourth be A,B,C,D: then
we are given :
1. B/D = 8/5
2. A/B = 3/4
3. C/D = 3/2
we want A/C:
A/C = A/B * B/C = A/B * (B/D * D/C) = 3/4 * (8/5*2/3) = 4/5

Hence E

Let me know if this helps :)
Join the discussion