Mike drove 10 miles in 30 minutes, what's the average speed in miles per hour

Mike is driving 20 miles per hour

If he is driving 10 miles in 30 mins
(1/2 an hour) if you times both by two it tells you the MPH that Mike is driving.

the law of definite proportions states samples of a compound will always contain the same proportion of elements by mass. in other words, a given compound will always contain the same elements in the same proportions by mass.the law of multiple proportions states when two elements combine with each other to form more than one compound, then the weights of one element that combine with a fixed weight of the other are in a ratio of small whole numbers.