What Is the Percent Efficiency (E)of an Engine If the Input

Multiple Choice

What is the percent efficiency (E) of an engine if the input (I) is 20,000 calories and the output (P) is 6,200 calories? Use the formula: $$E = \frac { I - P } { I }$$

A) 1.45
B) 0.69
C) 2.23
D) 0.45