Alliteration because pours and potions both have p's (i'm pretty sure)
This is true for any decimals below 1:
If you multiply a number by something greater than 1, it increases
If you multiply a number by 1, it stays the same
If you multiply a number by something less than 1, it decreases
You want one of the values in the ratio to be one for a unit rate. First, write out the ratio. It is 70 miles/2 hours. It's better not to include decimal numbers when you write a ratio when you can, so we're going to make the hours the unit rate. To make 2 -> 1 hour, divide both sides of the ratio by 2. 70/2 = 35.
The unit rate is 35 mi./hr.
Hope that helped you.