Question

19. When the members of a high school club are

arranged in rows of 2, 3, or 4, there is one
person always left over. But when the club
members are arranged in rows of 5, no one is
left over. What is the least number of people
who could be in the club?
À 15 people
C 45 people
B 25 people D 85 people

Answer 1

9514 1404 393

Answer:

B. 25 people

Explanation:

The remainders tell you the number will be 1 more than some multiple of the least common multiple (LCM) of 2, 3, and 4. The LCM is 3·4 = 12, so we want some multiple (n) of that such that 12n+1 is a multiple of 5. We know this is the case for n=2.

The least number of people who could be in the club is 2·12+1 = 25.