On cooling a 50 mole % solution of ethyl bromide and benzene, which freezes faster. Assume to be ideal
Some givens:
                          MW            Kf            Tf(°C)
Ethyl Bromide       109            12.12         7
Benzene               78             5.0            7

Thank you in advance for your help

please give the complete question

Unfortunately that is the entire question 

besides assume the solution to be ideal.

what other information do i need?

ΔTf = molality * Kf * i, ( i = Van 't Hoff factor)



use this equation