2002 AMC 12A Problem 17

Attempt Problem 17 of the 2002 AMC 12A below, then check your answer against the professionally curated solution from LIVE by Po-Shen Loh. You can also try the full timed exam, view all 2002 AMC 12A solutions, or check the answer key.

All problems are used with official legal permission of the Mathematical Association of America (MAA).

17.

Several sets of prime numbers, such as {7,83,421,659},\{7, 83, 421, 659\}, use each of the nine nonzero digits exactly once. What is the smallest possible sum such a set of primes could have?
193193
207207
225225
252252
477477
Answer: B
Concepts:primedigitsoptimization
Small hint:
The digits 4,6,84, 6, 8 cannot end a prime past one digit, so each must be a tens digit
Big hint:
Those three contribute at least 40+60+80,40 + 60 + 80, and the remaining six digits at least their own sum as units digits; then check a valid set exists
Solution:
The even digits 4,6,84, 6, 8 cannot be the units digit of a multi-digit prime, so each must appear in a tens place or higher, contributing at least 40+60+80=180.40 + 60 + 80 = 180. The other six digits contribute at least 1+2+3+5+7+9=27,1 + 2 + 3 + 5 + 7 + 9 = 27, so the sum is at least 207.207.
This bound is achieved, for example by {2,3,5,41,67,89},\{2, 3, 5, 41, 67, 89\}, whose sum is 207.207.
Thus, the correct answer is B.
LIVE by Po-Shen Loh
Programs

LIVE Classes

Self-Paced Classes

Stars

Scholarship

About Us

Who Is Po-Shen Loh?

Email Contact

Newsletter

Jobs

Become a Star

For a more Thought Full world.

© 2026 Expii, Inc.