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

Redeem
TTP OnDemand GMAT Video Course
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
Start Free 5-Day Trial Read 559 Reviews →

The sum of the squares of two prime numbers is 173. What is

Expert replies
Post new topic Post Reply
Previous Topic Next Topic
User avatar
Elite Legendary Member
Posts: 3991
Joined: Fri Jul 24, 2015 2:28 amFollowed by: 37 members
Location: Las Vegas, USA
Thanked: 19 times
by Max@Math Revolution » Tue Jul 30, 2019 12:20 am

Timer

00:00

Answers

A

B

C

D

E

Stats

Difficulty—

[GMAT math practice question]

The sum of the squares of two prime numbers is 173. What is the sum of the two prime numbers?

A. 5
B. 8
C. 10
D. 15
E. 16
Top
Join the discussion
Log in to postLogin with Googleuse password
QUOTE IN REPLY
Source: — Problem Solving |

GMAT/MBA Expert

User avatar
GMAT Instructor
Posts: 16207
Joined: Mon Dec 08, 2008 6:26 pmFollowed by: 1268 members
Location: Vancouver, BC
Thanked: 5254 times
GMAT Score:770

by Brent@GMATPrepNow » Tue Jul 30, 2019 5:38 am
Max@Math Revolution wrote:[GMAT math practice question]

The sum of the squares of two prime numbers is 173. What is the sum of the two prime numbers?

A. 5
B. 8
C. 10
D. 15
E. 16
\
Let x and y be the two primes.
So, x² + y² = 173

Since the sum of the squares is ODD, we know that one square must be EVEN, and the other square must be ODD.
Since 2 is the only even prime, the only way for the square of a prime to be even is when that prime is 2.
Let's say x = 2
We now have: 2² + y² = 173
In other words: 4 + y² = 173
In other words: y² = 169
Solve: y = 13

So, the sum of the prime numbers = 2 + 13 = 15

Answer: D

Cheers,
Brent
Brent Hanneson - Creator of GMATPrepNow.com
Image
Top
Join the discussion
Log in to postLogin with Googleuse password
QUOTE IN REPLY
User avatar
Elite Legendary Member
Posts: 3991
Joined: Fri Jul 24, 2015 2:28 amFollowed by: 37 members
Location: Las Vegas, USA
Thanked: 19 times

by Max@Math Revolution » Wed Jul 31, 2019 10:51 pm
=>

Let the prime numbers be p and q.
Then p^2 + q^2 =173, and one of p and q must be an even number and the other must be an odd number. Since the unique even prime is 2, we can set p = 2.
Then p^2 + q^2 = 4 + q^2 = 173 and q^2 = 169.
Therefore, q = 13 and p + q = 2 + 13 = 15.

Therefore, D is the answer.
Answer: D
Top
Join the discussion
Log in to postLogin with Googleuse password
QUOTE IN REPLY

GMAT/MBA Expert

User avatar
GMAT Instructor
Posts: 8157
Joined: Sat Apr 25, 2015 10:56 amFollowed by: 29 members
Location: Los Angeles, CA
Thanked: 43 times

by Scott@TargetTestPrep » Mon Aug 05, 2019 6:10 pm
Max@Math Revolution wrote:[GMAT math practice question]

The sum of the squares of two prime numbers is 173. What is the sum of the two prime numbers?

A. 5
B. 8
C. 10
D. 15
E. 16
13^2 + 2^2 = 169 + 4 = 173

13 + 2 = 15

Answer: D

Scott Woodbury-Stewart
Founder and CEO
[email protected]

Image

See why Target Test Prep is rated 5 out of 5 stars on BEAT the GMAT. Read our reviews

ImageImage
Top
Join the discussion
Log in to postLogin with Googleuse password
QUOTE IN REPLY
Post new topic Post Reply
• Page 1 of 1