Answer:
4.123 * 10∧4 kg
Explanation:
mass of car M' = 3.34 * 10∧4 kg
energy loss E = 19/100 Â K
from law of conservation of momentum ,
         M' V' = ( M' + M'' ) v
            V = M' V' / ( M' + M'' )
    Initial kinetic energy is K'  = (M' V')² / 2
   final kinetic energy  K" = 81 K' /100
                       =  (M' V')² 81 / (200)   =  ( M' + M'' ) v²/ 2
      therefore , M' / ( M' + M" ) = 0.81
 mass of caboose is ,  M" = 1.234 M' - M'
                   M" = .234 M'
                     = 0,234 ( 3.34 * 10∧4 kg)
                     = 4.123 * 10∧4 kg