Track / Stage 4 / 95 of 340 #355 of 2000

Problem 355

AMC 12 late, AIME early

Number theory Difficulty 4.7 Find the answer

3. How many of these five expressions give answers which are not prime numbers?
$1^{2}+2^{2}$
$2^{2}+3^{2}$
$3^{2}+4^{2}$
$4^{2}+5^{2}$
$5^{2}+6^{2}$

A 0
B 1
C 2
D 3
E 4

Your answer

Official solution

3. B The values of the five expressions are $5,13,25,41$ and 61 respectively. Of these, only 25 is non-prime.

Source: NuminaMath-1.5, licensed Apache-2.0. Statement and solution reproduced as published; topic, difficulty and ordering added by this site.