I think it's D. To sum the fractions, we need a common denominator. First, we need to know the least common multiple of 36 and 64.
Factor the 2 numbers into their prime factors:
36 = 2*2*3*3 = (2^2)*(3^2)
64 = 2*2*2*2*2*2 = (2^6)
The LCM can be found by multiplying together the highest power of each prime factor that occurs in the 2 numbers. Therefore,
LCM(36,64) = (2^6)*(3^2) = 576.
This will be our common denominator to sum the fractions, so
(1/36) + (1/64) becomes (16/576) + (9/576) = (25/576).
Then sqrt(25/576) = 5/24.
BREAKING: Target Test Prep releases Brand New 2026 On Demand GMAT prep course
Redeem
Featured Course
Target Test Prep GMAT OnDemand
Scott Woodbury-Stewart’s private virtual classroom — 400 hours of master-class video lessons for the GMAT Focus Edition.
- 715+ score guarantee — highest in the industry (99th percentile)
- 52 chapters · 1,500+ lessons · 4,000+ practice questions
- 400 hours of video · 1,500+ instructor-led HD smartboard lessons
- 300,000+ students accepted to Harvard, Stanford, Wharton, Booth & Sloan & more
- 24/7 live support + weekly Zoom office hours with GMAT instructors
- TTP AI Assist — 24/7 AI-powered virtual tutor for instant help
- 1,200+ flashcards + AI-powered study assistant & daily calendar
- OnDemand, LiveTeach & GMAT Bootcamp formats available
- Also: GRE, SAT Math & Executive Assessment courses
- MBA Admissions Consulting now available
- 🏆 2025 EdTech Breakthrough Award: Test Prep Solution Provider of the Year
- 200,000+ students served
- 5-day free trial — $0 to start, no auto-billing, cancel anytime
★★★★★
5.0
(559 reviews)
130-pt guarantee
$0 to start
then $127/mo
square root question
Source: Beat The GMAT — Problem Solving |
The ans should be D
we have sqrt (1/36 +1/64)= ?
cross multiply 1/36 +1/64
= sqrt (36+64/36X64)
=sqrt(100/36X64)
=sqrt (100)/sqrt(36)Xsqrt(64)
= 10/6.8
=5/24
we have sqrt (1/36 +1/64)= ?
cross multiply 1/36 +1/64
= sqrt (36+64/36X64)
=sqrt(100/36X64)
=sqrt (100)/sqrt(36)Xsqrt(64)
= 10/6.8
=5/24
Regards
Samir
Samir
