two masses m and 2m, approach each along a path at right angles to each other. after collision, they stick together and move off at 2m/s at angle 37° to the original direction of the mass m. what were the initial speeds of the two particles

Aprisoner is forced to go into one of three rooms, but he can choose which room. the first room is ablaze with fire. the second one is rigged with explosives that will go off as soon as he enters. the third contains a pair of lions who haven't eaten in years. which room should he choose to survive?