Question

nearly how much calories of work can be obtained from 250 calories of heat?

Answer 1

Work(in joules) = Joule's constant * Heat(in calories)  => W = J*H
where the value of J = 4.18 joules/calorie
W = J*H
    = 4.18 * 250
    = 1045 joules
As 1 joule = 0.2 calories
      1045 joules = 209 calories....this is the answer..!
Hope u have understood....excuse me if its not the answer u want..

Answer 2

209 or 210(aproxx) calories of work can be obtain from 250 calories
This is your answer 
ask me if you want explaination