Mr. and mrs. storey drove 3,200 miles in all during their vacation. mr. storey drove 3 times as much as mrs. storey. how many miles did mr. storey drive? just put equation, this will be on my maths test and i want to understand not just get the answer.

Mr. drove 3 times more then Mrs.. ok

so how far Mrs. drove will be X
and Mr. will be Y
but we know that Mr. drove 3 times more then Mrs therefor 
Y= 3X

and the Sum = 3,200

3,200=X+Y
3,200= X+(3X)
3,200=4X
div both by 4
800=X
now we know how far Mrs drove now to find Mr.
again "Mr. drove 3 times more then Mrs"
800 * 3 = 2,400

I’m pretty sure the slope would be 1 since the x and y values increase by 1