Finding the Exhaust Temperature of a Carnot Engine

[minszue]

Homework Statement

A Carnot engine performs work at the rate of 360 kW while using 720 kcal of heat per second.If the temperature of the heat source is 650 C, at what temperature is the waste heat exhausted?

Homework Equations

because Th,Qh,and W are given so i going to use this formula
W=Qh*[1-Tc/Th)

The Attempt at a Solution

the answer is too large and that is incorrect.

 

[rock.freak667]

Did you convert 720 kcal/s to kW properly?