A calorimeter of negligible heat capacity contains `50 m`. of water at `40^(circ) C`. The water cools to `35^(circ) C` in `50 min`. The water is now replaced by another liquid of equal volume at `40^(circ) C`. The time taken (in min) for the temperature to become `35^(circ) C` under similar condition is [density of liquid `=0.8` ' (density of water), specific heat of liquid `0.5` (specific heat of water)]

Answer

20