Browse · MATH Print → jmc algebra junior Problem The function f(x) satisfies xf(y)=yf(x)for all real numbers x and y. If f(15)=20, find f(3). Solution — click to reveal Setting y=3 and x=15, we get 15f(3)=3f(15)=60,so f(3)=4. Final answer 4 ← Previous problem Next problem →