Las notas del curso a tuvieron una media aritmetica de 75 puntos y un varianza de 225 las del curso b tuvieron una media de 70 puntos y una varianza de 196. si en ambos cursos las notas se aumentan en 10% cuales de los dos cursos tienen un coeficiente de variacion mayor despues de arreglar las notas

Athin walled concentric tube exchanger is used to cool engine oil from 160°c to 60°c with water that is available at 25°c acting as a coolant. the oil and water flow rates are each at 2 kg/s, and the diameter of the inner tube is 0.5 m and the corresponding value of the overall heat transfer coefficient is 250 w/m2. oc. how long must the heat exchanger be to accomplish the desired cooling? cpwater=4.187 kj/kg-candcpengine el=2.035 kj/kg·°c, oil . 120]