AoPSWiki
Looking for a challenging geometry text? Preparing for MATHCOUNTS or the AMC exams? Check out Art of Problem Solving's Introduction to Geometry by Richard Rusczyk.

2000 AMC 10 Problems/Problem 8

From AoPSWiki

Problem

At Olympic High School, \frac{2}{5} of the freshmen and \frac{4}{5} of the sophomores took the AMC-10. Given that the number of freshmen and sophomore contestants was the same, which of the following must be true?

\mathrm{(A)} There are five times as many sophomores as freshmen.

\mathrm{(B)} There are twice as many sophomores as freshmen.

\mathrm{(C)} There are as many freshmen as sophomores.

\mathrm{(D)} There are twice as many freshmen as sophomores.

\mathrm{(E)} There are five times as many freshmen as sophomores.

Solution

Let f be the number of freshman and s be the number of sophomores.

\frac{2}{5}f=\frac{4}{5}s

2f = 4s

f=2s

There are twice as many freshmen as sophomores. \boxed{\text{D}}

See Also

2000 AMC 10 (ProblemsResources)
Preceded by
Problem 7
Followed by
Problem 9
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25
Want to learn how to tackle those tough AMC/AIME/Olympiad algebra problems? Check out Art of Problem Solving's Intermediate Algebra by Richard Rusczyk and Mathew Crawford. Over 1600 problems!
© Copyright 2008 AoPS Incorporated. All Rights Reserved. • FoundationPrivacyContact Us