Sam and liam raced each other up and then down the hill. sam's average speed up the hill was 1 mph, and his average speed down the hill was 9 mph. liam ran up the hill and down the hill with the same speed, 2 mph. if the path from the bottom to the top of the hill is 1 mile long, how much time did it take each of the boys to finish - and who was the winner?

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

a 4/6 = 9/12   not proportional

step-by-step explanation:

to find which are not proportional, we can use cross products

if it is true, they are proportional.   if it is not true, they are not proportional.

a 4/6 = 9/12

4* 12 = 6*9

48 = 54

not this is not proportional  

b 2/3 = 12/18  

2* 18 = 3 * 12

36 = 36

this is proportional

c 5/4 = 10/8  

5*8 = 4*10

40 = 40

this is proportional

d 7/5 = 35/25

7*25 = 5 * 35

175 = 175

is proportional

6. 104

7. 52/37

8. 2704

9. 140608

10. -52

11. |52|=52

12. 1/52

13. 156

14. 26

15. 40

16. 37

17. -364

18. 53 1/3

19. 50.96

20. 43 2/3

21. 78

22. 50.75

23. 47.63

24. 163.28

25. 10400

26. 338

27. 208

28. 2704 square inches

29. 312 square meters

30. don't know what its asking, tell me so i can tell you

31. 8490.56

32. 52 degrees would be an acute angle

33. 128 degrees

34. 20.8

35. 39

36. 208