1963 TMTA High School Algebra I Contest Problem 27

Problem

If $A$ varies directly as $B,$ and if $A=5$ when $B=3,$ then the value of $A$ when $B=15$ is:

$\text{(A)} \quad 25 \quad \text{(B)} \quad 50 \quad \text{(C)} \quad 75 \quad \text{(D)} \quad 3/5 \quad \text{(E)} \quad 5/3$

Write this as a proportion: $\frac{A}{B}=\frac{5}{3}=\frac{x}{15}.$ We get $A = \boxed{\text{(A)} \quad 25}.$

1963 TMTA High School Mathematics Contests (Problems)
Preceded by Problem 26	TMTA High School Mathematics Contest Past Problems/Solutions	Followed by Problem 28