Weird collision question?

Question

A ball of mass m makes a head-on elastic collision with a second ball (at rest) and rebounds with a speed equal to one-fourth its original speed. What is the mass of the second ball?

Answer 1

in a completely elastic mv(1)= mv(2) so m2 = mv(1)/v(2) and v1= 1/4V(2) so therefore m2=4m(1)