So r is a number that when you add to t it will increase so its
T + r
So, we know that it takes Sam 1 mph up and 9 mph down and it takes Liam both 2 mph down and up the hill. So if we divide the 2 mph for Liam by 2 miles (the whole length of the hill) we will get 1 or 1 hour. Then we do 1/1 (i don't know how to explain this part of why we do that, sorry) and than we do 1 / 9 and we get 1/9 so we add them and get 1 1/9 so that's Sam's time.
So, Liam took one hour and Sam took 1 and 1/9 hours, in conclusion liam was faster
<h2> (I'm really sorry for my bad explaining, i tried my best)</h2>
Step-by-step explanation:
hundreds
