Track / Stage 4 / 38 of 340 #298 of 1964

Problem 298

AMC 12 late, AIME early

Algebra Difficulty 4.6 Find the answer

1. Set
$A=\{1,3,5,7\}, B=\{2,4,6,8,20\} \text {. }$

If $C=\{s \mid s=a+b, a \in A, b \in B\}$ , then the number of elements in set $C$ is:

Pick one

Official solution

-1. B.
Note that $s$ is odd, with a minimum value of 3 and a maximum value of 27, and it is missing 17 and 19. Therefore, set $C$ has a total of 11 elements.

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