If you're driving one and a half miles per minute, slow down by 15 miles per hour, and then reduce your speed by one third, how fast are you going now?

Before we do anything, we need to find out how fast we are going in the first place. 

We know we are going 1.5 miles per minute and that there are 60 minutes in an hour, so we can find our speed in mph. All we have to do is multiply 60 and 1.5.

That gives us 90 mph.

Next, the problem says that we reduce our speed by 15 mph, so you would subtract 15 from 90.

That gives us 75 mph.

The last thing the problem says is that we reduce our speed by one third, so first we need to know what one third of 75 is. We can find that by dividing 75 by 3.

That gives us 25

But we aren't finished yet! We still need to subtract 25 from 75 to get our current speed. When we do this we get our final answer of...

50 mph

If you need any further explanation, just let me know!