Cash outflows are costs of project and are represented by

negative numbers
positive numbers
hurdle number
relative number

The correct answer is A. negative numbers.

Cash outflows are costs of a project and are represented by negative numbers. This is because cash outflows represent money that is leaving the project, while cash inflows represent money that is coming into the project.

Option B is incorrect because positive numbers represent cash inflows. Option C is incorrect because a hurdle number is a minimum acceptable return on investment. Option D is incorrect because a relative number is a number that is expressed as a percentage or ratio of another number.