What colors make red?

I've been asked to paint a large scale piece of artwork with oil based paint, the ones you use on houses that don't dry quickly or blend easily. No problem, I got around that problem however, they gave me the wrong color RED which is more of a MAROON, a reddish brown, a mahogany brown.

I sent it back to them months ago telling them that is the wrong color red and the red won't match the shirt color of the students shirt (because the painting is for a school).
They just gave it back to me and told me the women at the paint shop, said that 'to just add 'white or black' and I will get red.'

How exactly do I get red out of mahogany brown? And how do I make red? Because I know red is a primary color and I know you don't make primary colors.
Correct me if I'm wrong, but which paints do you make the color RED like the primary color red out of?